Going by the List of Popes at Catholic Encyclopedia one finds that the name John has been most popular among the incumbents to the position. But what is intriguing is that no Pope after the first one adopted the name Peter which in fact, had been given to Simon by the Lord himself. Is there any reason for the same?

I was checking out the list of [pope names by frequency](http://en.wikipedia.org/wiki/Papal_name) on Wikipedia in search of minutia to defend my assertion that Pope Francis was the [first new Pope name a long time](http://christianity.blogoverflow.com/2013/03/14/5678-pope-francis-starts-with-a-clean-slate/?cb=1) and noticed that there were two popes named Pelagius ([I](http://en.wikipedia.org/wiki/Pope_Pelagius_I) and [II](http://en.wikipedia.org/wiki/Pope_Pelagius_II)) but there's also a [Pelagian heresy](http://en.wikipedia.org/wiki/Pelagian_heresy) that predates their pontificate. So, why Pelagius? Or didn't the Popes think that hard about their names back then?

Now beyond the obvious - such as the fact that you can’t select the name and monicker of a real Pope in the past, are there any specific regulations on the naming system?