Áedán mac Gabráin
In the west were the Gaelic (Goidelic)-speaking people of Dál Riata with their royal fortress at Dunadd in Argyll, with close links with the island of Ireland, from which they brought with them the name Scots. In 563 a mission from Ireland under St. Columba founded the monastery of Iona off the west coast of Scotland and probably began the conversion of the region to Christianity. The kingdom reached its height under Áedán mac Gabráin (r. 574–608), but its expansion was checked at the Battle of Degsastan in 603 by Æthelfrith of Northumbria.