The Roman Catholic Diocese of Saint-Hyacinthe is a Latin rite suffragan of the Metropolitan Archdiocese of Sherbrooke in Quebec, (predominantly francophone) Canada.

Its cathedral episcopal see is Cathédrale Saint-Hyacinthe-le-Confesseur, dedicated to diocesan patron saint Hyacinth the Confessor (of Poland), in Saint-Hyacinthe, Quebec.

Bishop Prince showed untiring activity, founding twenty new parishes, establishing several missions, and in 1853 introducing from France the Sisters of the Presentation of Mary.

The Sisters of Charity of the Hôpital Général of Montreal arrived in Saint-Hyacinthe in 1840 and soon established the Hotel-Dieu to provide health care for the community.

During his tenure, the contemplative institute Sisters Adorers of the Precious Blood was founded in Saint-Hyacinthe by Catherine Aurelia Caouette.

He closed the episcopal palace and relocated with his staff to the Église Saint-Matthieu-de-Belœil, where he combined the duties of bishop and pastor.