Áedán mac Gabráin
By the mid 6th-century, the Dál Riata in Scotland came under serious threat from Bridei I, king of the Picts, whilst the Irish portion faced hostility from the Dál nAraidi of Ulaid, resulting in their seeking the aid of the Irish Northern Uí Néill. Dál Riata reached its greatest extent in the reign of Áedán mac Gabráin, who was said to have been consecrated by Columba, who Áedán granted the island of Iona off the coast of Scotland. Columba, who was also a Cenél Conaill prince, negotiated an alliance between Dál Riata and the Cenél Conaill, who were the ruling dynasty of the Northern Uí Néill, in 575 at the Convention of Druimm Cete near Limavady. In attendance were Columba, Áedán mac Gabráin, and Áed mac Ainmuirech, king of the Northern Uí Néill and High King of Ireland.