The main structure was completed in 1846. In 1847, the church was designated the cathedral of Bytown and Joseph-Bruno Guigues was appointed the first bishop. He is honoured with a lifesize statue at the southwest corner of the cathedral grounds. In 1859, Father Damase Dandurand, OMI, designed the two Gothic spires which were added to the west front in 1866. Earlier, in 1849-50, he designed the Archbishop's Palace and in 1862-63, added the choir loft. In 1879, Pope Leo XIII designated the cathedral as a minor basilica.