Requested by Colonel Robert R. McCormick, to honor the memory of his first wife, the Sainte-Amélie Church was built between 1937 and 1939. The first Mass was celebrated, in the basement, on June 19th 1940.
The church's uniqueness lies in the fact that it is decorated with 1,500 square meters of frescoes and dozens of stained glass windows by Italian artist Guido Nincheri, whose artistic merits were recognized by the Vatican.
In 1945, following the division of the diocese, the church was consecrated Cathedral until May 15th 1960. The first bishop of the Diocese of the Gulf of St. Lawrence, Bishop Napoléon-Alexandre Labrie, was inducted on the 11th of August 1946.