Aonghas Óg of Islay married Áine Ó Catháin, an Irish noblewoman, whose dowry was 140 men from each surname that dwelt in her father's territory.
The Uí Catháin of Cenél nEógain originated in the Laggan area of County Donegal, and from there moved eastwards in the twelfth century, ousting the Uí Conchobair from Keenaght and retaining their lordship of Keenaght and Coleraine until the seventeenth century.