In 465 Eoghain, son of Niall of the Nine Hostages, died of grief for Conall Gulban, son of Niall of the Nine Hostages, and was buried at Uisce Chain, in Inis Eoghain; concerning which was said:

Eoghan, son of Niall, died

Of tears,—good his nature,—

In consequence of the death of Conall, of hard feats,

So that his grave is at Uisce Chain.

Eogan father of 11 sons Muiredach, Binech, Fergus, Echen, Oengus, Dallan, Cormac, Illann, Feideilmid, Eochaid, Ailill and from these 11 sons we get the Cenél Eóghain. In the 9th century the Cenél Eóghain were the dominant Northern dynasty. Establishing their power base at Inishowen and their capital at Aileach.

The Cenél Eóghain produced the Royal Houses of Ulster and the powerful MacLauchlan’s of Ulster.

A sept is an English word for a division of a family, especially a division of a clan. The Gaelic word slíocht, meaning seed, indicating the descendants of a person. This was then divided into septs by individual lines who further sub-divide into still more septs, which in turn sometimes led to a new surname, and/or the emergence of the family considered a clan in their own right.

A Progenitor is historical terms, the founder of a particular family. 

A Cenél an old Irish word usually glossed as ‘race, tribe, nation, or kindred’. It was used to describe a descent group in both early Ireland and Gaelic Scotland.