Muirchertach mac Muiredaig (Mac Ercae)

Muirchertach mac Muiredaig (died 943) was King of Ailech and High King of the Northern Uí Néill. He was a member of the Cenél nEógain branch of the Uí Néill dynasty. His patronymic indicates he was the son of Muiredach mac Eochada, and his nickname or secondary patronymic was Mac Ercae.

Muirchertach's reign was marked by extensive military campaigns throughout Ireland, primarily focused on extracting tribute and asserting the dominance of the Northern Uí Néill. He led expeditions into Connacht, Leinster, and Munster, often engaging in battles and raiding monasteries. These campaigns are frequently detailed in the Annals of Ulster and other Irish chronicles, emphasizing his activity and military prowess.

His claim to the High Kingship of the Northern Uí Néill is generally accepted, although the title itself was often contested and held concurrently by other powerful rulers in Ireland. He succeeded his kinsman Domnall mac Aeda as the dominant figure within the Northern Uí Néill.

Muirchertach mac Muiredaig was killed in 943. His death is recorded in the annals, marking the end of his influential reign. His legacy is primarily as a powerful warrior king who actively expanded the influence of the Cenél nEógain.