“Well, yes,” she nodded. “It’s only artificial, but it provides the bearer with the same type of power as Michael. It is a sword that lets you freely control the power of not just an archangel, but the leader of the angels. It can hardly be called a normal sword.”
[...]
“However, it can only be used within the boundaries of the United Kingdom. Basically, the Curtana is a sword that provides a large amount of Telesma to the queen and the knights,” she explained bluntly. “Basically, there is a special rule that only take affect within the four cultures of England, Scotland, Wales, and Northern Ireland and the three factions of the royal family, the knights, and the Anglican Church exist to enforce that rule. The Curtana functions as a sword that provides great power to those who enforce that rule and protect the United Kingdom.”
[...]
“That means it’s the second one. Historically, the Curtana Original disappeared somewhere. This Curtana Second was hurriedly created so there wouldn’t be any hindrances to the ceremony. So even if this one was broken, a new Curtana could be made. You don’t need to worry too much.”

Toaru Majutsu no Index Vol.17 ch.3 pt.4