Originally Posted by
Akoue
A lot depends here on what one means by the word "denomination". In one sense of the word there were no denominations until well after 325. In another sense of the word, though, there were lots of denominations before 325: There were Marcionites, Valentinians, Basilideans, Montanists, Arians, Donatists, etc. Groups, in other words, that for various reasons broke off from the main body of Apostolic Churches (each of the groups I mention were around before 325) which recognized themselves as a single body until well after the Council of Nicaea.