The first architect was Sir Thomas Drew, the foundation stone being laid on 6 September 1899 by the Countess of Shaftesbury.

[1] In 1924 it was decided to build the west front of the cathedral as a memorial to the Ulstermen and women who had served and died in the Great War.

Edward, Lord Carson, the leader of the Unionist cause at the time of the Home Rule Crisis, was buried (with a state funeral) in the south aisle of the cathedral in 1935.

The south transept, containing the Chapel of Unity, and with the organ loft above, was dedicated in 1974, and the north transept, with the large Celtic cross designed by John MacGeagh on the exterior, and housing the Chapel of the Royal Irish Rifles, was completed in 1981.

Named the "Spire of Hope", the structure is illuminated at night and is part of a wider redevelopment planned for the Cathedral Quarter.

[3] The base section of the spire protrudes through a glass platform in the cathedral's roof directly above the choir stalls, allowing visitors to view it from the nave.