John Ostell's first work in Montreal was the city's original Custom House; then he also submitted designs for the new St. James Cathedral in Toronto in 1849.
John Ostell (7 August 1813  6 April 1892) architect, surveyor and manufacturer, was born in London, England and emigrated to Canada in 1834, where he apprenticed himself to a Montreal surveyor Andre Trudeau to learn French methods of surveying. His first work in Montreal was the city's original Custom House, completed in 1836. Ostell submitted designs for the new St. James Cathedral in Toronto in 1849, placing second in the competition to Frederick William Cumberland. 
