What is a Sept
Septs were groups of descendents of a common ancestor who inhabited the same locality. These groups were smaller subsets of ancient clans. The members of the sept shared a common surname. In the case of the O'Cathains had various sub-septs under their authority, these sub-septs carried out many important roles within the O'Cathain Sept. The O'Mullans provided a warrior class of Galloglasses, which were called to battle at the request of their O'Cathain masters. The McIlvenny sept acted has hereditary 'ollavs' to the O'Cathains, custodians of the national memory and of oral literature. The O'Diamond Sept provided ''Erenaghs' and 'coarbs' functioned as stewards, collecting rents and tithes.
Sources of O'Cahan Confederate Septs
In 1608 in "Chichester's Instructions "we read; "The Chiefs Septs in the country of Coleraine are the O'Cathains and under them the O'Mullans, the Magillans and the Mccloskeys. "O'Mullans, Magilligans, McCloskys, O'Diamonds, O'Toghills and other families were subject to the O'Cathains and paid tribute to him.