Colla Uais

The Three Collas (Modern Irish: Trí Cholla) were, according to medieval Irish legend and historical tradition, the fourth-century sons of Eochaid Doimlén, son of Cairbre Lifechair. Their names were: Cairell Colla Uais; Muiredach Colla Fo Chrí (also spelt Colla da Chrioch, or Fochrich); and Áed Colla Menn. Colla Uais ruled as High King of Ireland for four years. However, the chronology of early Irish historical tradition is regarded by historians as artificial. One story makes Fiachra Cassán of the Airgíalla, son of Colla Fo Chrí, the foster-father of Cormac mac Airt, who according to the usual chronology was his own great great grandfather, and an alternative tradition dated the fall of Emain Macha to 450.

The sixth century female saint, Derchairthinn, associated with Oughter Ard near Straffan, County Kildare, was said to be "of the race of Colla Uais, Monarch of Érinn".

Historical interpretation According to a theory advanced by T. F. O'Rahilly, the traditional story of the Three Collas is not historical, although it has a basis in history. O'Rahilly argues that the breaking of the power of the Ulaid, the destruction of Emain Macha and the establishment of the kingdoms of the Airgialla were actually accomplished by the three sons of Niall Noígiallach, Conall, Endae and Eógan, who established the kingdoms of Tir Eógan and Tir Conaill in north-western Ulster in the mid-5th century. He believes the Three Collas are literary doublets of the three sons of Niall, their story a genealogical fiction intended to give the tributary kingdoms of the Airgialla a noble pedigree.

This theory is followed by more recent historians, including Francis J. Byrne, and Dáibhí Ó Cróinín.

Donald Schlegel claims the brothers' tripartite names to be the only examples in ancient Ireland of brothers using the Roman style naming convention of personal name followed by family name followed by an epithet. This may reflect their alleged "return" from exile in Alba, which at the traditional time of their story—the 4th-century—was part of the Roman Empire. Schlegel suggests that being put in command of 300 soldiers may have meant that were centurions in the Roman army.