Christ Church Cathedral Christ Church Cathedral or the Cathedral of the Holy Trinity is the oldest cathedral in Dublin. Founded around 1030 by the Hiberno-Norse, it has welcomed worshippers for nearly a millennium. It it is the mother church of the Church of Ireland United Dioceses of Dublin and Glendalough. The roof, the south nave and west walls collapsed in 1562. It was extensively rebuilt in the 1870s with Victorian Gothic features.