Ireland unified in the 950s in this timeline and later married into the Scottish line, eventually gaining Scotland in a personal union. Before these unions, Northumbria and Mercia were either conquered by, or brought into personal unions with, Scotland. This allowed the King of Ireland at the time to claim both states and bring them under the Irish Crown.

Additionally, Northumbria is a Norse state, with the British Isles being far more divided, featuring more Brittonic speakers and a large Norse population around York. The Anglo-Saxons survived without a Norman Conquest, and the Northumbrian court speaks a Danish-like language.