Between 1851 and 1881, Cornwall experienced a large-scale industrial expansion which in turn led to an influx of workers and tradesmen from Quebec. The city saw its French Catholic community grow to 1,323 from just 323 out of a total population of 4, 468.

To meet the spiritual needs of the growing French-speaking community, Father J.J. Kelly (1884-1887) was called upon to organize a French parish dedicated to the Blessed Virgin Mary.

In 1976 the church was elevated to the status of Co-Cathedral with St. Finnan Cathedral in Alexandria.