Cathedral High School is a public Roman Catholic high school in Hamilton, Ontario, under the administration of the Hamilton-Wentworth Catholic District School Board. Cathedral High School dates back to 1912, when high school classes where offered to the youth of Hamilton by the Hamilton Separate School Board. Classes were held in two rooms at St. Mary’s School, located on Mulberry Street. By 1921, enrollment had increased significantly and the two rooms could no longer hold the amount of people. The boys were soon moved to the upper floor of St. Patrick’s School on East Avenue and Main Street. While the girls remained at St. Mary’s. In 1925, the Separate School Board authorized the building of a new and larger building.