<ul class="list">
   <?
   $history = array(
     "p1" => array("from"=>"a",  "to" => "b", "title"=>"c", "company"=>"d", "skills"=>array("s1","s2")),
     "p2" => array("from"=>"a",  "to" => "b", "title"=>"c", "company"=>"d", "skills"=>array("s1","s2"))
     );
   foreach ($history as $v=>$k): {?>
           <li><em class="period"><?= $k['from']?> - <?= $k['to']?></em><strong><?= $k['title']?> as <?= $k['company']?></strong></li>
           <ul class='skills'>
           <?php foreach ($k['skills']as $print_skill):?>
             <li><a href=""><?= $print_skill ?> </a></li>
           <?php endforeach;
           ?></ul><?

       }
   endforeach;
   ?>

</ul>


-- running --
boris@galt:~$ php x.php
<ul class="list">
              <li><em class="period">a - b</em><strong>c as d</strong></li>
           <ul class='skills'>
                        <li><a href="">s1 </a></li>
                        <li><a href="">s2 </a></li>
           </ul>           <li><em class="period">a - b</em><strong>c as d</strong></li>
           <ul class='skills'>
                        <li><a href="">s1 </a></li>
                        <li><a href="">s2 </a></li>
           </ul>
</ul>