There is an old story told in the North about Coel's last campaign. What is now Scotland was originally inhabited by both Brythonic and Pictish tribes. It was during Coel's time that immigrant Irishmen of the Scotti tribe began to settle the Western coast around Argyle. Coel, fearing that these Northern peoples would unite against his domain south of Hadrian's Wall, sent raiding parties across his northern border to stir up discord between them. The plan, however, backfired for the Picts and the Scots were not taken in. Coel merely succeeded in pushing the two even closer together, and they began to attack the British Kingdom of Strathclyde. Coel declared all out war and moved north to expel the invaders. The Picts and Scots fled to the hills ahead of Coel's army, who eventually set up camp at what became Coylton alongside the Water of Coyle (Ayrshire). For a long time, the British were triumphant, while the Scots and Picts starved. Desperate for some relief, however, the enemy advanced an all-or-nothing attack on Coel's stronghold. Coel and his men were taken by surprise, overrun and scattered to the winds. It is said that Coel wandered the unknown countryside until he eventually got caught in a bog at Coilsfield (in Tarbolton, Ayrshire) and drowned. Coel was first buried in a mound there before being removed to the church at Coylton. The year was about AD 420. After his death, tradition says that Coel's Northern kingdom was divided between two of his sons, Ceneu and Gorbanian.