The Gaelic kingdom of Dál Riata

There is evidence that the Gaelic kingdom of Dál Riata was established in the 5th century by King Fergus Mór (Fergus the Great). The kingdom was located on the western seaboard of Scotland and the north-eastern coast of Ireland, on either side of the North Channel. It consisted of four main kindreds, each with its own chief: Cenél nGabráin (based in Kintyre), Cenél nÓengusa (based on Islay), Cenél Loairn (who gave their name to the district of Lorn), and Cenél Comgaill (who gave their name to Cowal). The capital of Dál Riata was believed to be the hillfort of Dunadd, and other important royal forts included Dunollie, Dunaverty, and Dunseverick.

The kingdom of Dál Riata was known for its seafaring culture and large naval fleet. It was also home to the important monastery of Iona, which played a key role in the spread of Celtic Christianity and the development of insular art. Iona was a centre of learning and produced many important manuscripts.

During the reign of King Áedán mac Gabráin (574–608), Dál Riata experienced a period of expansion. The kingdom carried out naval expeditions to Orkney and the Isle of Man, and made attacks on the Brittonic kingdom of Strathclyde and the Anglian kingdom of Bernicia. However, the growth of Dál Riata was checked by King Æthelfrith of Bernicia at the Battle of Degsastan in 603.

In the 7th century, Dál Riata suffered serious defeats in Ireland and Scotland during the reign of Domnall Brecc (died 642), marking the end of the kingdom’s “golden age.” Dál Riata became a client of Northumbria for a time. In the 730s, the Pictish king Óengus I led campaigns against Dál Riata and brought it under Pictish overlordship by 741.

There is disagreement among scholars about the fate of Dál Riata after this point. Some believe that the kingdom experienced a revival under King Áed (736–778), while others see it as having effectively come to an end. Some even suggest that Dál Riata may have usurped the kingship of Fortriu. From the late 8th century onward, there were sporadic Viking raids in Dál Riata. In the following century, there may have been a merger of the Dál Riatan and Pictish crowns. Some sources indicate that Cináed mac Ailpín (Kenneth MacAlpin) was king of Dál Riata before becoming king of the Picts in 843, following a major defeat of the Picts by Vikings. The kingdom of Dál Riata eventually merged with Pictland to form the Kingdom of Alba.