The parish now known as St. Peter's was established 10 August 1834 and the first church was constructed of logs at the southwest corner of Dufferin Avenue and Richmond Street.

The new church was located at the northeast corner of Dufferin and Richmond, just in front of the present structure.

The Diocese of London was created in 1856 and Bishop Pierre-Adolphe Pinsoneault selected St. Lawrence as his cathedral renaming the church St. Peter's.

[clarification needed] He selected Joseph Connolly as architect[2] and construction began in July 1880.

In 1958, the twin towers of the facade, Lady Chapel, and sacristy were added, stained glass windows were installed in the narthex and additional interior painting and decoration completed.