In 1848, Irish Catholics celebrated their first mass in Biddeford in the Emery House at the foot of Emery Street with Father McGuire of the parish of St. Dominic's in Portland. Around 1850, Catholics began gathering on the second floor of the offices in the Pepperell Mills, where mass was said about every three months by a priest from Portland. The congregation then moved to St. Mary's Church, first known as the Church of the Assumption, built by Patrick C. Keely in 1856 on Vetromille Street, later renamed St. Mary's Street. French-Canadians originally attended mass at St. Mary's until they moved to the old Methodist church in 1870. After a fire destroyed the church, rebuilding began in 1923, and dedication was held in 1926.