After the Catholic Archbishop of Armagh, William Crolly , had long campaigned for a Catholic cathedral, construction began on St. Patrick's Day in 1840 , after a committee for the construction of a cathedral was established . The first architect Thomas Duff died in 1848 during the construction work. In 1853 JJ McCarthy took over his job. In 1904 the cathedral was completed and consecrated by Michael Logue .
The cathedral is 63.3 m long. Pope Pius IX sent a copy of Raphael's Madonna of Foligno to Armagh. The Emperor of Austria also presented a gift to Armagh Cathedral. Armagh Cathedral is one of the largest church buildings in Ireland.
organ
The organ in the west stand was built in 1875 by the organ builder William Telford. The instrument originally had 33 registers on three manuals and a pedal and was equipped with Barker machines. In 1904 the organ was reorganized by the Telford & Telford organ builders; in this context the organ was u. a. equipped with pneumatic action and the wind pressure was increased. In 1987 the organ was rebuilt, expanded and rebuilt by the Irish organ builder Antrim. a. a fourth manual, and newly intoned. The instrument has 58 stops on four manual works and a pedal.