High King of Ireland
Royal title
High King of Ireland was a royal title in Gaelic Ireland held by those who had, or who are claimed to have had, lordship over all of Ireland. The title was held by historical kings and was later sometimes assigned anachronously or to legendary... Wikipedia
Past holders: Brian Boru, Niall of the Nine Hostages, Ruaidrí Ua Conchobair, and more
First monarch: Sláine mac Dela (mythical); Máel Sechnaill I (historical)
Last monarch: Ruaidrí Ua Conchobair
Residence: Hill of Tara
Style: Ardrí na hÉireann; Rí Érenn Uile; Imperator Scottorum