On June 29th, 1867 the corner stone of the church was laid and the foundation blessed by Very Rev. Dr. John Cameron. Sylvester O'Donoghue, a native Irishmen, built the Cathedral. Originally, the architect Owen Hamill was retained to design and oversee the construction of the Church but he died prematurely in 1868. As such, St. Ninian's was completed by architect A. Levesque of Montreal.