This must be wrong so. http://en.wikipedia.org/wiki/Roger_Casement
Roger Casement - Ruairí Mac Easmainn.
Rory is an anglicisation of Ruairí, so the two names are effectively the same, and valid "translations" of one another. Similarly (so far as I know, anyway) Pól is a gaelicisation of Paul, so the words serve as translations of one another.
There is another phenomenon: the matching of Gaelic names with English ones, often on the basis of some similarity. That's fairly arbitrary. Taking Ruairí as the Irish for Roger is one such arbitrary match. Another arbitrary match that I think odd is setting Abigail as the translation for Gobnait. But who is the gainsay anybody saying "My name in English is Jeremiah; In Irish, I wish to be known as Diarmaid"? There is no right or wrong involved.
It might become interesting as our "new Irish" with given names from Eastern Europe or from Africa proceed through the school system, and some of them become enthused by the Irish language. What if little Jumoke decides that she wants to be known in Irish as Gráinne?