Joseph Octave Plessis, a Canadian bishop, born in Montreal, March 3, 1762, died in Quebec, Dec. 4, 1825. He was ordained priest in Quebec March 11, 1786, and became secretary to the bishop and rector of the cathedral. Elected coadjutor to Bishop Denaud Sept. 6, 1797, the captivity and death of Pius VI. prevented the ratification of his choice at Rome till April 28, 1800, when he was confirmed with the title of bishop of Canata. His election by the church of Canada and his confirmation by the pope gave rise to a long controversy with the British government. The kings of France had exercised the right of presentation to all bishoprics, as well as that of confirming the election of bishops when made by the local clergy. The same right was claimed by the English crown after the conquest of Canada; but the claim was strenuously and successfully resisted by Bishop Plessis. He was consecrated in Quebec, Jan. 25, 1801, and became titular bishop Jan. 17, 1806. In 1818 he was appointed by the crown a member of the legislative council of Canada. After becoming titular bishop he raised the standard of learning in the existing colleges, founded at his own expense the college of Nicolet, and multiplied primary schools.

He also displayed great zeal in providing for the spiritual wants of the Indians, and made several fruitless attempts to obtain the recall of the Jesuits and other missionaries. In 1819 he visited London and Rome for the purpose of having British North America organized into an ecclesiastical province, with an archbishop at Quebec and suffragan bishops in the principal cities and missionary centres; but he only succeeded in having auxiliary bishops appointed for Montreal, Halifax, and the Indian missions of the Red River district. He left several pastoral letters, a collection of Latin synodal addresses, and a manuscript journal of his journey to Europe. - See J. B. A. Ferland's "Life of Bishop Plessis.