It is the cathedra of the Archbishop of Cashel and Emly and stands on the site of earlier chapels, which were the only Roman Catholic churches in Thurles.

Following the English Reformation, many archdiocesan assets, including the cathedral at the Rock of Cashel were appropriated by the established church.

James Butler II (1774–91),[1] on being appointed by the Holy See, moved his residence and cathedra from Cashel, favouring Thurles instead, where his successors continue to reign today.

From the time of the English Reformation onwards, those archbishops appointed by Rome had to make their throne in whichever house in County Tipperary would hide them from the forces of the Crown.

The building has many architectural features, including an impressive rose window, a baptistery, and its most important possession is a tabernacle of Giacomo della Porta, a pupil of Michelangelo.