Kingdom of Leinster

Origins

The Laigin, the people of Leinster, appear in the earliest Irish traditions as a major power whose kings once held the midlands and Tara. From the 5th century the rising Uí Néill drove them south, and Leinster settled into an over-kingdom covering most of the south-east, contested between dynasties such as the Uí Dúnlainge in the north and the Ui Chennselaig in the south.

Rule and society

Kings ruled through tribute and alliances with subject peoples, and great monasteries such as Kildare, Glendalough and Ferns flourished. Brandub mac Echach defeated the high king at Dún Bolg in 598. Viking Dublin lay within Leinster, and from the 11th century its kings sought to control it; Diarmait mac Máel na mBó, who died in 1072, ruled Dublin and nearly became high king.

Decline and legacy

In 1166 Diarmait Mac Murchada was expelled and sought help from Henry II. Anglo-Norman knights led by Strongbow, who married Diarmait's daughter Aoife, took Wexford, Waterford and Dublin. On Diarmait's death in 1171 Strongbow claimed Leinster, and Henry II's arrival brought it under the English crown.