was witnessed by Aedh Mor Magennis, who was cited as being chief of Clann Aodha and of Iveagh. The Magennises are also mentioned in letters by King Edward II, where they are titled Dux Hibernicorum de Ouehagh, meaning "chief of the Irish of Iveagh".

The Magennises allied themselves to the Earldom of Ulster, which was created after the Norman invasion of Ulster, until the death of William Donn de Burgh, 3rd Earl of Ulster