The Assassination of Tigernán Ua Ruairc, The Last King of Meath

The expansion of Tigernán Ua Ruairc, king of Uí Briúin Bréifne, into the province of Meath in the mid-twelfth century ultimately led to his eclipse of the Uí Máel Sechlainn. His control of the region caused the Anglo-Norman baron Hugh de Lacy to assassinate him, with the aid of an exiled noble of Bréifne. This article investigates the motives, personalities, and locations concerned in the assassination, and shows that the Irish noble involved in killing Ua Ruairc was an Ua Ragallaig, not another Ua Ruairc, as previously thought.