Five Fifths

…of tuatha, known as the Five Fifths (Cuíg Cuígí), occurred about the beginning of the Christian era. These were Ulster (Ulaidh), Meath (Midhe), Leinster (Laighin), Munster (Mumhain), and Connaught (Connacht).

… ultimately became grouped into the Five Fifths. Among these, Ulster seems at first to have been dominant; but, by the time Niall of the Nine Hostages died early in the 5th century, hegemony had passed to his midland kingdom of Meath, which was then temporarily associated with Connaught. In the…