The school was established as an all girls private school in 1847 by Irish Sisters of Loreto (also known as the Institute of the Blessed Virgin Mary, also known as IBVM, founded in France by the Venerable Mary Ward, an English recusant, in 1609). Ward advocated excellent education for young women so that they might “do great things” and this has always formed part of the ethos of Loretto schools. The Loreto Sisters arrived in Toronto from Rathfarnham, Ireland, in 1847 at the invitation of Michael Power, the first Roman Catholic bishop of Toronto. The school was named after their previous home of Loreto Abbey near Dublin. The first Superior of the Toronto community and principal of the school was Mother Teresa Ellen Dease, I.B.V.M.