In 1177, Courcy led an invasion of Ulaid (an area roughly encompassing what is today County Antrim and County Down). He reached Down (modern day Downpatrick), drove off Ruaidrí Mac Duinn Sléibe, King of Ulaid, consolidated his conquest, and ruled his lands with a certain amount of independence for about a quarter of a century. Although the date of the marriage between Courcy and Affrica is uncertain, the union may well have attributed to his stunning successes in Ireland. The rulers of Ulaid and those of Mann had a bitter past-history between them, and it is possible that Courcy's marital alliance with the Crovan dynasty was the catalyst of his assault upon the Ulaid. In fact, Guðrøðr Óláfsson formalised his marriage to Findguala in 1176/1177, and thereby bound his dynasty with the Meic Lochlainn of Cenél nEógain, another traditional foe of the Ulaid. Courcy would have almost certainly attempted to use such alignments to his advantage, whilst Guðrøðr Óláfsson would have used Courcy's campaigning against the Ulaid as a means of settling old scores.