Pierre Dumoulin-Borie was a French Catholic missionary priest and titular bishop of Acanthus who served in Vietnam during the early 19th century. Born in Beynat in 1808, he joined the Paris Foreign Missions Society and was ordained in Bayeux in 1830. After traveling to Macao, he entered Saigon to support the South Tonkin mission despite local prohibitions. His dedicated service led to his arrest and eventual execution in 1838, making him one of the Vietnamese Martyrs.