Plé:Tomás Ó Criomhthain

Different names

This Author is mentioned with several Names. In the Irish original of An t-Oileánach he calls himself Tomás Dhomhnaill, the English translation of this is transcribed as Tomás Donel. But in the same book the author is named Tomás O'Crohan whilst Wikipedia calls him Tomás Ó Criomhthain. I'm not sure what to make of it. Donel and Dhomhnaill or O'Crohan and Ó Criomhthain seems to be a transliteration from one language to another but how does Donel relate to O'Crohan or Dhomhnaill to Ó Criomhthain? Ogmios ^(Tratsch) 12:23, 9 Bealtaine 2015 (UTC)