Missionary; b. Boston, Mass., May 15, 1758; d. Limerick, Ireland, Feb. 17, 1815. He was the fourth of eight sons of Cornelius and Sarah (Plaisted) Thayer, who were members of the First Church (Unitarian), in Boston. After brief service as a tailor's apprentice, he attended Yale University, in New Haven, Connecticut, leaving in the third year but receiving an honorary A.B. in 1779. He served as chaplain for militia men on Governor's Island in Boston Harbor from 1780 to 1781. He next visited Europe, where Italian hospitality, contact with former Jesuits, and the canonization process of St. Benedict Joseph Labre all served to impress him with Catholicism, and he entered the Church in 1783. His published account of his conversion was widely read. A short stay at the English College in Rome, followed by three years of study at the Seminary of Saint-Sulpice in Paris, culminated in his ordination there on June 2, 1787.
In 1789 Thayer was sent to Boston, where Father Louis de Rousselet was stationed. There then began a period of dissension between the French and the Irish factions in Boston that ultimately led to court action. When Archbishop Carroll recognized Thayer as the pastor, the French stayed aloof from church, one parishioner going so far as to have a Protestant burial. Thayer's temperament was finally judged unsuitable for the Boston assignment, and in 1792 he departed for a mission in Virginia. After several years in New York, Albany, and Canada, he went to work in the Kentucky missions, where he championed the abolition of slavery long before social and civil conditions made it practical. In 1804, he left the United States, and after a year in London and another at La Trappe, France, he went to Ireland, spending some years in Dublin before moving to Limerick in 1811. Thayer's entire estate was willed to found an Ursuline convent and school in Boston.
Bibliography: j. thayer, An Account of the Conversion of the Reverend J. Thayer (Baltimore 1788; London 1800; Dublin 1809). r. h. lord et al., History of the Archdiocese of Boston … 1604 to 1943, 3 v. (Boston 1945).
[t. f. casey]