Galileo Galilei (Renaissance and Reformation)

Introduction

Galileo Galilei (c. 15 February 1564–8 January 1642) or Galileo, as he is usually referred to, is often regarded as the founder of the science of physics. His remarkable insight enabled him to focus on those properties of matter that could be modeled in a mathematical way. He overthrew the rigidified Aristotelian viewpoint of his contemporaries. The concepts of velocity and acceleration lay at the heart of his reforms. Through a series of experiments, he discovered the relationships between distance, velocity, and acceleration obeyed by falling bodies. Galileo was the first person to use the telescope seriously for astronomy and in doing so he discovered the moons of Jupiter, the first clear example of bodies in orbit around a center other than the earth. He became an outspoken advocate of the Copernican model of the universe. He discovered the phases of Venus. He also claimed to have discovered sunspots and he found that the sun rotates. His abrasive and outspoken criticism of Aristotelian philosophy and his obvious acceptance of the Copernican worldview, particularly in his Dialogue concerning the Two Chief World Systems (see Florentine Period), led him into serious trouble with the Roman Catholic Church, which placed him under house arrest for the last eight years of his life. He was nevertheless able to continue writing and research.

Complete Works

Though an attempt was made to publish a “complete works” by Galileo’s pupil Vicenzo Viviani, the definitive edition is Le Opera di Galileo Galilei edited by A. Favaro (Favaro 1890–1909).

Favaro, A. (the Galileo scholar), ed. Le Opere di Galileo Galilei: Edizione nazionale sotto gli auspicii di sua maestà il re d’Italia. 20 vols. Florence, Italy: Barbèra, 1890–1909.
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The standard edition of Galileo’s works. Reprinted 1929–1939 and 1964–1966.
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Principal Works

Many of Galileo’s works have been re-published in modern Italian editions and have been translated into other languages. The following concentrates on his most significant works and some of their English translations. The book that earned Galileo international fame was his Siderius Nuncius of 1610 (see Galilei 1989, cited under Paduan Period). In it he describes his development of the telescope and the various findings he made with it. Here are announced his discoveries of the craters on the surface of the moon, the fact that far more stars can be seen than those visible to the naked eye, and the so-called “Galilean Moons” of Jupiter. He dedicated the book to Cosimo II de’ Medici, flattering him by calling the four newly discovered moons the “Medicean Stars.” The standard translation is that by van Helden (Galilei 1989, cited under Paduan Period). In his book of 1612 on “Bodies that stay atop water or move in it” (see Drake 1981), he reported on some of his early work that clarified the legacy of Archimedes. He showed that many of Aristotle’s assertions were incorrect. Other important works around this time were “Sunspots” (1613; see Galilei 1957a), “Letter to the Grand Duchess” (Galilei 1957b), “Discourse on Tides” (see Galilei 1989), and Discorso Delle Comete (1619, see Drake and O’Malley 1960). Galileo’s most famous work and the one that led to his being tried by the Holy Office was his Dialogue concerning the Two Chief World Systems: Ptolemaic and Copernican (1632; see Galilei 1967, cited under Florentine Period). In this work, Galileo’s own views are put forward by a character called Salviati. He and a rather dense Aristotelian called Simplicio argue the case for each “world system” before an intelligent neutral person called Sagredo. Needless to say, Galileo favored the Copernican viewpoint. Galileo had undertaken to present the pope’s Aristotelian arguments in the book but, by placing them in the mouth of the unfortunately named Simplicio, he succeeded in antagonizing the holy father. The Dialogues concerning Two New Sciences was Galileo’s last major work and that of greatest relevance to the history of physics. Though less “controversial” that the World Systems, Galileo nevertheless had it smuggled out of Italy to be printed by the Elseviers in Leiden (1638; see Galilei 1954, cited under Florentine Period). The two new sciences were mechanics and “Local Movements.” It is in this book that his work on velocity and acceleration was published.

Drake, S., trans. Cause, Experiment and Science: A Galilean Dialogue Incorporating a New English Translation of Galileo’s “Bodies That Stay atop Water, or Move in It.” Chicago and London: University of Chicago Press, 1981.
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An idiosyncratic presentation and translation of Discorso … intorno alle Cose, che Stanno in l’acqua, che in Quella si Muovono (1612) as a dialogue.
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Drake, S., and C. D. O’Malley. The Controversy on the Comets of 1618. Philadelphia: University of Pennsylvania Press, 1960.
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Contains an English translation of Discorso Delle Comete (1619).
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Galilei, G. “Letters on Sunspots.” In Discoveries and Opinions of Galileo. Translated by S. Drake. New York: Doubleday, 1957: 89–144
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Translation of Istoria e Dimostrazioni Intorno alle Macchie Solari (1613).
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Galilei, G. “Letter to the Grand Duchess Christina.” In Discoveries and Opinions of Galileo. Edited by S. Drake. New York: Doubleday, 1957b: 173–216
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Translated version of Lettera a Cristina di Lorena, Granduchessa di Toscana (1615, first published 1636).
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Galilei, G. “Discourse on the Tides.” In The Galileo Affair: A Documentary History. Edited and translated by M. Finocchiaro, 119–133. Berkeley: University of California Press, 1989.
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A translation of Discorso sul Flusso e il Reflusso del Mare (1616).
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Specialized Journals and Critical Reviews

A number of journals contain articles on Galileo in English from time to time, including the British Journal for the History of Science, Galileana: Journal of Galilean Studies, Isis, Osiris, and the Journal for the History of Astronomy. Critical reviews of relevance have appeared on occasion in the Journal for the History of Astronomy (see for example Brooke 1996 and McMullin 2009).

British Journal for the History of Science.
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A journal covering the history of science generally that contains articles relevant to Galilean studies from time to time.
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Brooke, J. H. “Matter of Fact and Faith.” Journal for the History of Astronomy xxvii (1996): 68–74.
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A critical comparative review of works such as Reston 1994 and Sharratt 1994 (both cited under Biographies).
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Galileana: Journal of Galilean Studies.
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An annual publication devoted to detailed Galilean studies, written in various languages.
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Isis.
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This journal is published by the University of Chicago Press on behalf of the History of Science Society and has contained over the years many articles on Galilean matters as well as reviews of works concerning Galileo.
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Journal for the History of Astronomy.
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Occasionally contains articles relevant to Galileo and interesting reviews of the ever-burgeoning literature.
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McMullin, E. “The Galileo Affair: Two Decisions.” Journal for the History of Astronomy 40 (2009): 191–212.
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A review of various books and documents on the trials in 1616 and 1633 with many references.
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Osiris.
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This series is published by the University of Chicago Press on behalf of the History of Science Society. Each volume is devoted to a general theme in the history of science.
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Biographies

Works about Galileo fall into two broad categories: those that are about his contributions to science and those that deal with his problems with the Roman Catholic Church. As in the case of Isaac Newton, the literature about Galileo is very extensive. The first biography is a short one by Vincenzio Viviani (see Viviani 1890–1909), Galileo’s last pupil, written about twelve years after his death. The veracity of some of the information it contains is dubious (Segre 1989). Drake, for many years the best-known scholar of Galileo writing in English, wrote in 1978 what has long been considered the finest all-around biography of Galileo, especially in regard to scientific matters (Drake 1978). A recent well-researched and less hagiographic biography, which can now probably be regarded as the most thorough, especially in terms of setting out the social background of Galileo’s life, is Heilbron 2010. The modern short biography Glass 2006, derived from secondary sources and recent papers, is one of eight short biographies of astronomers who have revolutionized our thinking in one way or another. Reston 1994 gives a human picture of the life of Galileo with popular and serious aspects. Many biographies of Galileo deal with him from a Roman Catholic viewpoint. Sharratt 1994 is one such general biography placing some emphasis on Galileo’s problems with the church but in general having a broad, modern outlook. It covers in part the Pontifical Commission to investigate the Galileo case that was set up in 1981. A popular but fairly comprehensive biography, though based on the letters of Galileo’s daughter, is Sobel 1999. Many of these letters were published before, in the 19th century, in Allan-Olney 1870.

Allan-Olney, Mary. The Private Life of Galileo. London: Macmillan, 1870.
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Originally anonymous. Based on the correspondence of Galileo with his daughter, Virginia, who became a nun under the name of Sister Marie Celeste. Some information about Galileo’s father, Vincenzio Galilei.
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Drake, Stillman. Galileo at Work: His Scientific Biography. Chicago and London: University of Chicago Press, 1978.
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The most comprehensive modern biography of Galileo in regard to scientific matters.
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Glass, Ian S. “Galileo: Seeing and Believing.” In Revolutionaries of the Cosmos: The Astro-Physicists. By Ian S. Glass, 8–39. Oxford: Oxford University Press, 2006.
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A short biography giving Galileo’s contribution to our current world picture, in the context of revolutionary insights by “great astronomers.”
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Heilbron, John L. Galileo. Oxford: Oxford University Press, 2010.
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A modern general biography, particularly strong in portraying the societal background against which Galileo operated.
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Reston, James, Jr. Galileo: A Life. New York: HarperCollins, 1994.
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A popular account of Galileo’s problems with the church rather than his science.
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Segre, M. “Viviani’s Life of Galileo.” Isis 80 (1989): 206–231.
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Critical discussion of this first “life” and its limitations.
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Sharratt, Michael. Galileo: Decisive Innovator. Cambridge, UK: Cambridge University Press, 1994.
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A modern liberal Catholic view of Galileo.
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Sobel, Dava. Galileo’s Daughter: A Drama of Science, Faith, and Love. London: Fourth Estate, 1999.
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A biography partly based on letters from Galileo’s daughter, immured in a convent.
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Viviani, V. “Racconto istorico Della vita del Sig.r Galileo Galilei.” In Le Opere di Galileo Galilei: Edizione nazionale sotto gli auspicii di sua maestà il re d’Italia. 20 vols. Edited by A. Favaro, Vol. XIX, 597–632 Florence, Italy: Barbera, 1890–1909.
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This early biography contains the dubious assertion that Galileo disproved Aristotle by dropping weights from the Tower of Pisa. Reprinted 1929–1939 and 1964–1966.
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Early Years

Galileo’s family had at one time been among the leaders of Florentine society. His father Vincenzio was a cloth merchant but, more important, a musician of considerable ability who did experimental work on musical instruments to understand what determined the pitch of a note (see, for example, Galilei 1584). Galileo was given a traditional education in a monastery school and later studied medicine at the University of Pisa. The worldview then prevalent was Aristotelian, but Platonism and Neoplatonism were beginning to undermine its monopoly even before Galileo was born. The spread of the printed word contributed to the more rapid diffusion of new thinking. For example, the celebrated De Revolutionibus of Copernicus (Copernicus 1543) appeared in 1543. After attending the lectures of the mathematician Ostilio Ricci, whose lectures on Euclid were an eye-opener, Galileo lost interest in medicine and dropped out of university. For a few years he taught mathematics for a living and began to investigate the work of Archimedes. This led him toward work on the centers of gravity of bodies and eventually to contact in Rome with leading scientists of the Collegio Romano, the intellectual headquarters of the Jesuit order, from whom he learned contemporary scientific thinking. He was appointed during 1589–1592 to the University of Pisa, where he started to develop his ideas on mechanics and experiment with bodies rolling down inclined planes. He had by this time become thoroughly outspoken and did not hesitate to criticize colleagues with old-fashioned ideas.

Copernicus, N. De revolutionibus orbium coelestium. Nuremberg, Germany: Petreium, 1543.
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Copernicus’ main presentation of his world model.
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Galilei, Vincenzo. Fronimo: dialogo sopra l’arte del bene intavolare, et rettamente sonare la musica negli strumenti artificiali si di corde come di fiato, & in particulare nel liuto. 2d ed. Venice: Appresso l’Herede di Girolamo Scotto, 1584.
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A book on playing the lute and preparing vocal music for it.
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Paduan Period

In 1592–1610 he worked at Padua, in the relatively free atmosphere of the Republic of Venice, outside the strong influence of the Roman Catholic Church, which attempted to control thought in those parts of Italy under its political control, including the Duchy of Florence. This he regarded as the happiest part of his life. It was here that he developed his original scientific outlook. Instead of worrying about causes as the Aristotelians did, he concentrated on the mathematical description of the behavior of bodies, in other words, the science of kinematics. This approach was also characteristic of his contemporary, Johannes Kepler, and, later in the 17th century, of Isaac Newton. His great discoveries in telescopic astronomy (1610; see Galilei 1989 and the sections on Telescopes and Telescopic Observations) showed that the earth was not the only center of motion, as believed by the Aristotelians, but that bodies could be seen in orbit around the planet Jupiter. The discovery of the phases of Venus constituted evidence that it was in orbit around the sun and not the earth. In addition, the telescopic appearance of the moon showed that it is not a perfectly smooth crystalline sphere as believed by the Aristotelians.

Galilei, G. Sidereus Nuncius or the Sidereal Messenger. Translated by A. Van Helden. Chicago and London: University of Chicago Press, 1989.
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This is a translation of Galileo’s best-selling account from 1610 of his initial discoveries with the telescope, with footnotes and a bibliography.
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Florentine Period

In 1610 Galileo accepted a position in the Duchy of Florence in spite of the warnings of his friends that he was compromising his freedom. Nevertheless, his productivity continued unabated. However, in 1614 he began to experience serious attacks on the grounds of irreligiosity and in 1615–1616 he narrowly escaped the clutches of the Inquisition. In the following years he seriously antagonized the Jesuits, who had previously been friendly toward him, with his sarcastic publications critical of several of their scientists. In the 1620s he worked on his Dialogue concerning the Two Chief World Systems (1632; see Galilei 1967). Up to the point of publication he had enjoyed the support of the pope (Urban VIII), so long as he treated Copernicanism in a purely hypothetical way and did not claim outright that it was the truth. However, by placing the pope’s arguments in the mouth of a participant in the Dialogues called Simplicio (actually the name of a respected classical Aristotelian), he caused outrage and was summoned before the Inquisition once again. In his trial in 1633, he was forced to recant and sentenced to house arrest for the remainder of his life. In his last years he wrote his Discourses and Mathematical Demonstrations Relating to Two New Sciences, which were published in Leiden (1638; see Galilei 1954). He became blind toward the end of his life, but not before discovering the libration of the moon. To the end he discreetly maintained his Copernicanism (e.g., see Galilei 1985). He died in 1642, having the company in his last days of the physicists Evangelista Torricelli (1608–1647) and Vincenzio Viviani (1622–1703).

Galilei, G. Dialogues concerning Two New Sciences. Translated by H. Crew and A. de Salvio with an introduction by Antonio Favaro. New York: Dover, 1954.
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Though this translation dates originally from 1914 it still appears to be adequate. It is based on the version in the National Edition, edited by Antonio Favaro, one of the greatest of Galilean scholars. Originally published as Discorsi e dimostrazioni matematiche, Intorno a due nuove scienze in 1638.
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Galilei, G. Dialogue concerning the Two Chief World Systems: Ptolemaic and Copernican. 2d rev. ed. Translated by S. Drake. Berkeley: University of California Press, 1967.
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This edition of Galileo’s most famous work has an interesting introduction by Albert Einstein in which he questions whether the discoveries made by Galileo were inevitable or only a matter of time and not dependent purely on him. Originally published as Dialogo dei due massimi sistemi del mondo, Tolemaico e Copernicando in 1632.
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Galilei, G. “‘Letter to Rinnucini, 28 March 1641,’ quoted by O. Pedersen in ‘Galileo’s Religion.’” In The Galileo Affair: A Meeting of Faith and Science; Proceedings of the Cracow Conference, 24–27 May 1984. Edited by G. V. Coyne, M. Heller, and J. Życiński. 81. Vatican City: Specola Vaticana, 1985.
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“The falsity of the Copernican system ought not to be doubted in any way, and most of all not by us Catholics who have the undeniable authority of Holy Scripture, interpreted by the best theologians . . . but if the observations and conjectures of Copernicus are insufficient, those of Ptolemy, Aristotle and their followers are in my view even more false.”
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Scientific Method

In Galileo’s career we see the gradual development of scientific method. At first he attempted to build on the medieval Aristotelian approach that over-emphasized derivations using logic, often at the expense of observational facts. The early progress toward a more rational science was the subject of much Galilean research in the 20th century. Wallace 1977 and Machamer 1998 provide general introductions to this phase of his work; detailed papers can be found in Drake 1999 and in the journal Galileana (see Specialized Journals and Critical Reviews). As his methodology developed, Galileo used experimental and observational information to generate physical theories in an iterative fashion. In the course of this he developed clear ideas on velocity and acceleration, partly as a result of his careful experiments, which showed great skill and intuition in the emphasis he placed on observing only those parameters that were relevant to kinematics. With the telescope, partly developed by him, he opened a new world of celestial observations that made a convincing case for the Copernican model of the universe. However, he was surprisingly unaware of the work of Kepler and other contemporaries and sometimes allowed himself, for example in his theory of the tides, to be led astray by his own bombast. Koestler 1959 gives a rather idiosyncratic popular account of the early development of planetary astronomy, and is critical of Galileo. His later work is covered in books such as Drake 1978 and the other biographies cited under Biographies. In his Il Saggiatore (1623; see Galilei 1957), Galileo made a strong statement that nature has to be understood in mathematical terms.

Drake, S. Essays on Galileo and the History of Science. 3 vols. Selected and edited by N. M. Swerdlow and T. H. Levere. Toronto: University of Toronto Press, 1999.
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This is a collection of articles by the Galilean scholar Stillman Drake; about 100 out of 130 are on Galileo.
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Galilei, G. “The Assayer.” In Discoveries and Opinions of Galileo. Translated by S. Drake, 229–280. New York: Doubleday, 1957.
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Translated version of Il Saggiatore (1623), a reply to an attack by Grassi (see Galilei and Giuducci 1960 cited under Humor and Sarcasm), in which Galileo advocated the mathematical modeling of the universe.
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Koestler, A. The Sleepwalkers. New York: Macmillan, 1959.
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A somewhat journalistic and untrustworthy account of the development of early modern astronomy by Copernicus, Kepler, Galileo, and others. Galileo is denigrated for his neglect of Kepler’s work. However, it is indeed true that Galileo remained ignorant of his great contemporary’s “laws” of planetary motion.
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Machamer, P., ed. The Cambridge Companion to Galileo. Cambridge, UK: Cambridge University Press, 1998.
DOI: 10.1017/CCOL0521581788Save Citation »Export Citation »E-mail Citation »
A set of thirteen introductory articles to Galilean themes mainly written by philosophy and history of science specialists. Good chapters by W. A. Wallace, P. Machamer, and W. Hooper deal with the formation of Galileo’s earlier ideas.
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Wallace, W. A. Galileo’s Early Notebooks: The Physical Questions. Notre Dame, IN: University of Notre Dame Press, 1977.
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This book throws light on the early influence on Galileo’s thought of the Jesuits of the Collegio Romano.
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Telescopes

Galileo, on hearing of the existence of telescopes, invented probably by Lipperhey of Middleburgh, the Netherlands, and egged on by the friar Paolo Sarpi (see Pigatto 2010), soon learned how to build them for himself. By studying the manufacture of small concave lenses, he was able to achieve magnifications of up to thirty times, compared with the three times of the first instruments. A well-illustrated history of the early development of the telescope, associated with an exhibition originally held at the Istituto e Museo di Storia della Scienza in Florence, is Strano 2008. According to Greco, et al. 1992, optical tests of Galileo’s remaining lenses reveal their quality to have been surprisingly good. Reeves 2008 deals in detail with the period between the telescope’s creation and Galileo’s becoming acquainted with it ten months later. An important technical improvement in telescope design due to Galileo was the introduction of stops (Dupré 2003).

Dupré, S. “Galileo’s Telescope and Celestial Light.” Journal for the History of Astronomy 34.4 (2003): 369–399.
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Besides the use of stops to improve image quality, this author also discusses Galileo’s thoughts on the nature of the light from celestial bodies (whether reflected, etc.).
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Greco, V., G. Molesini, and F. Quercioli. “Optical Tests of Galileo’s Lenses.” Nature 358 (1992): 101.
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Examination of Galileo’s surviving lenses by modern methods.
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Pigatto, L. “Galileo and Father Paolo: The Improvement of the Telescope.” In Astronomy and Its Instruments before and after Galileo: Proceedings of the Joint Symposium Held in Venice, San Servolo Island, Italy, 20 September–2 October 2009. Edited by Luisa Pigatto and Valeria Zanini, 37–50. Padua, Italy: Cooperativa Libraria Editrice Università di Padova, 2010.
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Discusses the part played by Paolo Sarpi in Galileo’s early development of the telescope.
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Reeves, E. A. Galileo’s Glassworks: The Telescope and the Mirror. Cambridge, MA: Harvard University Press, 2008.
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Galileo and Sarpi did not react all that quickly to the discovery of the telescope. This book looks into the reasons why and to events around the time.
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Strano, G. Galileo’s Telescope: The Instrument That Changed the World. Florence, Italy: Giunti, 2008.
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Exhibition catalog: Florence, Istituto e Museo di Storia della Scienza, 4 March–31 December 2008. “Galileo’s Telescope,” part of the series of events celebrating the 400th anniversary of Galileo’s celestial discoveries.
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Telescopic Observations

Galileo’s initial fame rested on the discoveries he made with the telescope. Though he was not the first person to use one to observe heavenly bodies, his systematic approach and rapid deduction of new facts led to a highly deserved success. See Gingerich and van Helden 2003 for the genesis of his book Sidereus Nuncius. The dating of Galileo’s early observations of the lunar craters is controversial (Whitaker 1978, Gingerich 1984). It is further apparent that he exaggerated some features on his diagrams. The discovery of the phases of Venus supported the Copernican viewpoint against that of Ptolemy (Drake 1984), though it did not disprove the hybrid system advocated by Tycho. Gingerich 1984 investigates the appearance of the planet at the time of Galileo’s observations. Palmieri 2001 discusses the part played by Galileo’s student Castelli in this work. Galileo was the first person to observe the planet Neptune, seeing it twice—in 1612 and 1613. This slow-moving planet was also observed by several other astronomers before its “discovery” by Galle in 1846 (see Kowal and Drake 1980). Sunspot observations were of importance in the arguments against the Ptolemaic/Aristotelian viewpoint. They showed firstly that the sun rotated and secondly that it did not have a perfect, unblemished surface (see Mueller 2000).

Drake, S. “Galileo, Kepler and the Phases of Venus.” Journal for the History of Astronomy 15 (1984): 198–208.
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An account of the interaction of Galileo, Kepler, and various others on this issue, with translations of the relevant correspondence.
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Gingerich, O. “Phases of Venus in 1610.” Journal for the History of Astronomy 15 (1984): 209–210.
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Computer-synthesized images of Venus as it would have appeared in 1610.
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Gingerich, O., and A. van Helden. “From Occhiale to Printed Page: The Making of Sidereus Nuncius.” Journal for the History of Astronomy 34 (2003): 251–267.
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Concerns the way in which Galileo assembled and presented his observational materials.
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Kowal, C. T., and S. Drake. “Galileo’s Observations of Neptune.” Nature 287 (1980): 311–313.
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A pre-discovery serendipitous observation of the planet Neptune. Galileo was the first of a number of astronomers who recorded sightings of Neptune before its discovery by J. G. Galle in 1846.
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Mueller, P. R. “An Unblemished Success: Galileo’s Sunspot Argument in the Dialogue.” Journal for the History of Astronomy 31 (2000): 279–299.
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Concerns Galileo’s interpretation of the motion of sunspots across the face of the sun and its application to proving Copernicanism.
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Palmieri, P. “Galileo and the Discovery of the Phases of Venus.” Journal for the History of Astronomy 32 (2001): 109–129.
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Concerned with an accusation that Galileo stole this discovery from his pupil Benedetto Castelli.
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Whitaker, E. A. “Galileo’s Lunar Observations and the Dating of the Composition of Sidereus Nuncius.” Journal for the History of Astronomy ix (1978): 155–169.
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Galileo’s published images of the moon were somewhat impressionistic, but in this paper Whitaker attempts to date them from the lunar aspects calculated to have been visible around the time he was writing.
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Trouble with the Church

Following criticism by clerics of his outspoken views on biblical fundamentalism, Galileo was attacked at court by the widowed Grand Duchess of Tuscany, Christina. In a letter to her (see Galilei 1957) explaining his position, written in 1615, he openly admitted his Copernicanism. He also made a strong point that the church was asking for trouble by denying the manifestly obvious. The most senior cleric involved with monitoring Galileo’s opinions was Cardinal Bellarmine (see Westfall 1989), the leading intellectual figure of the Jesuit order, a member of the Inquisition and a stickler for orthodoxy. In 1616 the Inquisition condemned Copernicus’s views and Galileo received a warning that they were contrary to scripture. Blackwell 1991 discusses the theological problems that had arisen. Nevertheless, Galileo was still treated in a friendly way by the church authorities. He may or may not have been issued with a much more severe injunction that became a feature of his later trial on a “Vehement suspicion of heresy.” With the publication in 1632 of his Dialogue concerning the Two Chief World Systems: Ptolemaic and Copernican (1632; see Galilei 1967, cited under Florentine Period), he thoroughly antagonized the pope and set the scene for his trial before the Inquisition.

Blackwell, R. Galileo, Bellarmine, and the Bible: Including a Translation of Foscarini’s “Letter on the Motion of the Earth.” Notre Dame, IN: University of Notre Dame Press, 1991.
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Discusses the theological problems that led to the banning of a Copernican work by Paolo Antonio Foscarini, a contemporary of Galileo, and its placing on the list of Forbidden Books (Index Librorum Prohibitorum).
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Galilei, G. “Letter to the Grand Duchess.” In Discoveries and Opinions of Galileo. Translated by S. Drake, 145–171. New York: Doubleday, 1957.
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In this letter from 1615, Galileo explains his attitude to literal interpretation of the Bible and claims that he is defending the interest of the church.
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Westfall, R. S. “The Trial of Galileo: Bellarmine, Galileo and the Clash of Two Worlds.” Journal for the History of Astronomy 20 (1989): 1–23.
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The background to Bellarmine’s worries about Copernicanism, etc.
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The Trial

For many, the trial endured by Galileo is more interesting than his scientific achievements. It finds echoes in modern ideological controversies (e.g., De Santillana 1955). Many commentators take the view that, in the context of his time, Galileo was being unduly provocative and that church law and tradition prescribed that he had to be taken to task (e.g., Gingerich 2005, Finocchiaro 2005, Finocchiaro 2008). Criticism of his support of protestant powers may have encouraged the pope to prove his orthodoxy by prosecuting Galileo (Marshall 2008). There are numerous detailed accounts of the trial, among which we can mention Fantoli 2003 and Shea and Artigas 2005. Since his imprisonment, which amounted to a form of house arrest, Galileo has been seen as a martyr to official censorship. The English poet John Milton, a celebrated defender of press freedom, visited the imprisoned scientist and wrote (Milton 1927) “There it was that I found and visited the famous Galileo grown old, a prisoner to the Inquisition, for thinking in Astronomy otherwise than the Fransciscan and Dominican licencers thought.” (p. 35). A symposium in 2005 addressed the issues between Galileo and the church in the light of releases of information about the trial around that time (McMullin 2005).

De Santillana, Giorgio. The Crime of Galileo. Chicago: University of Chicago Press, 1955.
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A view of Galileo’s trial written somewhat in the light of the McCarthyite persecution of left-wingers in the United States. The Jesuits are regarded as having conspired to bring down Galileo.
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Fantoli, A. Galileo: For Copernicanism and for the Church. 3d ed. Translated by G. V. Coyne. Studi Galileiana, Vol. 6. Vatican City: Vatican Observatory Publications, 2003.
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Original Italian title: Galileo: Per il Copernicanismo e per la Chiesa. A version of the controversy that criticizes other works on this issue. It is critical of the church’s defense of its condemnation of Galileo.
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Finocchiaro, M. A. Retrying Galileo. Berkeley: University of California Press, 2005.
DOI: 10.1525/california/9780520242616.001.0001Save Citation »Export Citation »E-mail Citation »
Written after the rehabilitation of Galileo in the eyes of the Roman Catholic Church, this book suggests Galileo was not a heretic.
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Finocchiaro, M. A., ed. The Essential Galileo. Indianapolis, IN: Hackett, 2008.
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A collection of texts in translation illustrating some of the main themes of Galileo’s life, controversial and otherwise. Compared to Drake’s Discoveries and Opinions of Galileo (see Galilei 1957, cited under Humor and Sarcasm), more emphasis is placed on epistemological issues, as well as on scriptural interpretation and the trial documents.
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Gingerich, O. “Fresh Perspectives on the Galileo Affair.” Journal for the History of Astronomy 36 (2005): 443–447.
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An interesting critical review of two books: Finocchiaro 2005 and McMullin 2005.
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Marshall, D. M. “The Thirty Years War and the Galileo Affair.” History of Science 46 (2008): 49–74.
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Concerns political motivations for the church’s prosecution of Galileo.
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McMullin, E. The Church and Galileo. Notre Dame, IN: University of Notre Dame Press, 2005.
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A series of previously published but updated articles by some leading Galileo scholars discusses the topic in the light of the relatively recent release of the records of the Holy Office (Inquisition).
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Milton, J. Areopagitica: A Speech of Mr John Milton for the Liberty of Unlicenc’d Printing, to the Parliament of England. London: Douglas, 1927.
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In this tract (originally published in 1644), Milton argues against a proposed censorship law before the Parliament during the English Civil War.
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Shea, W. R., and M. Artigas. Galileo in Rome: The Rise and Fall of a Troublesome Genius. Oxford: Oxford University Press, 2005.
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Critically and negatively reviewed as being too sympathetic to the church by Fantoli, A. Journal for the History of Astronomy 36 (2005): 109–111.
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Aftermath of the Trial

Historically, the clash of Galileo with the church has always appealed to those who try to preserve freedom of thought. It took until the late 20th century for the church to openly apologize for its persecutions. In the meantime, Galileo was greatly admired by anti-clerical critics. The long-term development of attitudes toward Galileo has been described by Finocchiaro 1989 and Segre 1998. The unjustness of his treatment also appealed to a number of artists, who depicted him as a hero. He was several times portrayed defending himself in front of the Italian Inquisition (see Lewis 2007).

Finocchiaro, M. A. The Galileo Affair: A Documentary History. Berkeley: University of California Press, 1989.
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Contains edited and translated documents associated with the theological and philosophical arguments in Galileo’s defense of Copernican astronomy.
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Lewis, J. “Truth and Propaganda in Images of the Trial of Galileo.” Journal for the History of Astronomy 38 (2007): 15–29.
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Presents a number of images of the trial of Galileo, mainly depicting him as a martyr.
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Segre, M. “The Never-Ending Galileo Story.” In The Cambridge Companion to Galileo. Edited by P. Machamer, 388–416. Cambridge, UK: Cambridge University Press, 1998.
DOI: 10.1017/CCOL0521581788Save Citation »Export Citation »E-mail Citation »
Views on Galileo as hero and martyr as they developed over the centuries.
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Private Character

Galileo was tempestuous and ambitious in character but inwardly tender as seen from the letters from his daughter that have been preserved (Allan-Olney 1870, Galilei 2001). He was not irreligious, merely anti-clerical, as can be seen in Pedersen 1985. He appears to have taken astrology quite seriously: this was part of his job while working for the Medicis. However, the fact that he made horoscopes for his family and himself shows that he did not undertake these in a cynical way (Swerdlow 2004). He was not above tailoring the description of his astronomical discoveries to flatter the reigning Medici prince (Biagioli 1990), calling the four bright satellites of Jupiter the “Medicean stars.”

Allan-Olney, M. The Private Life of Galileo. London: Macmillan, 1870.
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Published anonymously. Many of the letters from Galileo’s daughter were first published here.
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Biagioli, M. “Galileo the Emblem Maker.” Isis 81 (1990): 230–258.
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Concerns Galileo’s ambition of securing the patronage of the Medici, such as by naming the moons of Jupiter after them. This paper also emphasizes the increasing appreciation at court for science and the glory it could bring to a ruler.
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Galilei, Maria Celeste. To Father: The Letters of Sister Marie Celeste to Galileo, 1623–1633. Translated and annotated by D. Sobel. London: Fourth Estate, 2001.
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Gives the Italian originals and their translations into English of the letters of his daughter Virginia (Sister Marie Celeste) to Galileo.
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Pedersen, O. “Galileo’s Religion.” In The Galileo Affair: A Meeting of Faith and Science; Proceedings of the Cracow Conference, 24–27 May 1984. Edited by G. V. Coyne, M. Heller, and J. Życiński, 75–102. Vatican City: Specola Vaticana, 1985.
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A careful examination of Galileo’s publications and letters reveals that he was, at least in outer behavior, a conventional believer. He never mentioned Jesus but certainly seemed to believe in prayer. He also made a pilgrimage on one occasion, something that must have required considerable effort.
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Swerdlow, N. M. “Galileo’s Horoscopes.” Journal for the History of Astronomy 35 (2004): 135–141.
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Among Galileo’s interests (and also his duties) was the construction of horoscopes for himself and his family. Inter alia, these show that his date of birth could have been either the 15th or the 16th of February 1564.
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Humor and Sarcasm

In defending himself Galileo often had recourse to sarcasm. An early example of this was his ribald poem Capitolo contro il portar la toga (Against the wearing of the gown) written when he was fined for not wearing his academic gown in public. In it he maintained that wearing of clothes was the root of all evil; without them social distinctions would be impossible. A critical discussion of the poem has been given by Heilbron 2010, cited under Biographies. It has been translated into English, using a similar rhythmic form, by Bignami 2000. Later on, Galileo’s sarcastic treatment of the astronomer Christopher Scheiner and other Jesuits probably contributed to increasing animosity toward him in church circles, leading eventually to his trial. In 1619 the Jesuit astronomer Orazio Grassi had anonymously published a pamphlet, An Astronomical Disputation on the Three Comets of the Year 1618. Galileo replied with his Discourse on the Comets, published under the name of a student, Mario Guiducci (1619; see Galilei and Guiducci 1960). In its opening passage, Galileo and Guiducci’s Discourse gratuitously insulted Scheiner. Grassi, using the pseudonym Sarsi, replied with The Astronomical and Philosophical Balance, which was intended to weigh his opponent’s arguments. The Assayer (see Galilei 1957) was Galileo’s reply.

Bignami, T. R., trans. Against the Donning of the Gown: Enigma. London: Moon Books, 2000.
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Translation in similar style of Galileo’s Capitolo contro il portar la toga (1690), an anti-establishment poem in terza rima. Considered an Italian literary classic.
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Galilei, G. “The Assayer.” In Discoveries and Opinions of Galileo. Translated by S. Drake, 229–280. New York: Doubleday, 1957.
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Abridged translation of Il Saggiatore (1623). Some of Galileo’s original ideas on scientific method are contained in this work.
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Galilei, G., and M. Guiducci. “Discourse on the Comets.” In The Controversy on the Comets of 1618. Translated by S. Drake and Charles Donald O’Malley. Philadelphia: University of Pennsylvania Press, 1960: 21–65
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Contains translations of the Grassi works as well as the Galileo/Guiducci 1619 Discourse.
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Imagery

Galileo was painted several times during his lifetime. Robert Derome’s online Index of Galileo Galilei Portraits can be recommended as a comprehensive guide. The National Maritime Museum, Greenwich, United Kingdom, has a portrait c. 1606 by Domenico Robusti (see Robusti 1606), when Galileo was about 42 years old. There are crayon portraits from 1624 by Ottavio Leoni (Bibliotheca Marucelliana, Florence; Louvre, Paris, cited here under Leoni 1624). There is a portrait of a troubled-looking Galileo of 1636 by Justus Sustermans in the Uffizi Gallery, Florence (Sustermans 1636). Another, c. 1640 by the same artist, showing him as a venerable figure holding a telescope, is in the National Maritime Museum, Greenwich (Sustermans 1640).

Derome, Robert. Index of Galileo Galilei Portraits.
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Comprehensive website on portraits of Galileo.
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Leoni, Ottavio. Portrait of Galileo Galilei. Bibliotheca Marucelliana, 1624.
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Portrait by Leoni.
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Robusti, Domenico. Galileo Galilei. National Maritime Museum, c. 1606.
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NMM portrait by Domenico Robusti.
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Sustermans, Justus. Portrait of Galileo. Uffizi, 1636.
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Uffizi portrait by Sustermans.
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Sustermans, Justus. Galileo Galilei. National Maritime Museum, c. 1640.
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NMM portrait by Sustermans.