Fr. Ryan of Sacred Heart Parish celebrated the first mass at St. Peter's School on Epiphany of 1959. Later, Monsignor Hughes said mass in one of the classrooms, then in the upstairs corridors of the school from 1959 to 1961. During these years, he visited the families in the parish and took over many of the duties of pastor.
The parishes of Sacred Heart and Canadian Martyrs were growing very rapidly, it was decided that for Catholics living west of Albert Street and north of the CNR tracks, that mass would be celebrated in St. Peter's School.
The parish boundaries were set from a point where the CNR tracks cross Albert Street, northward to the boundary of the city. Fr. A. Vandendriessche was appointed pastor of the new parish effective April 17, 1961 and celebrated the first mass on April 23, 1961.
The parish of St. Peter's grew in size over the next year and in the fall of 1962, plans to build a church with attached rectory and office began. The sod turning ceremony was held on September 15, 1963 with Monsignor Gerein officiating. Construction of the new church began on September 17, 1963. In November of 1963, a parish drive for funds was held and was very successful. The first mass was held on May 24, 1964.
Because of the steady increase in the number of families, Fr. George Cels was appointed an assistant in December, 1964. In September, 1965, Fr. Cels transferred and Fr. R. Chadwich was appointed assistant until 1967.
The parish grew rapidly until the boundaries were reorganized in September, 1967. A new parish (Holy Trinity) consisting of 300 families was formed west of Pasqua Street. 700 families remained at St. Peter's.
Following the recommendations of Vatican II, plans for the formation of a Parish Council took place in the fall of 1967. The first meeting was held January 14, 1968. Various council committees were formed which took some pastoral and financial responsibilities from the parish priest.
The present boundaries of St. Peter's Parish extend from Albert Street west to Pasqua Street and from the CN tracks to the north boundary of the city. The parish encompasses St. Peter & St. Timothy elementary schools and Archbishop M.C. O'Neill High School.