Pierre Marie Louis de Boisgelin de Kerdu (May 5, 1758 - September 9, 1816), also known as Caillot-Duval, was a French writer and militant monk. He was born at the Château de la Ville-Balin in Plélo, France. He studied at the seminary of Sant-Sulpice until 1782 when he was presented to the Order of St. John of Jerusalem, a Malta based militant monastic knightly order related to the Knights Templar. He left the Knights of St. John in 1793, but remained in Malta. When Malta was occupied by the French under Napoleon Bonaparte, in 1798, he joined the French armies. When the English retook the archipelago, in 1800, he fled to Toulon. There, he joined royalist forces, organizing with the support of Louis XVIII, the 'Royal Louis' regiment. When they were defeated by the Republican Army, Boisgelin fled to England, where he wrote and published his 1804, Ancient and Modern Malta and a supplementary large-scale map of Malta - the best yet seen. He returned to France in 1805 where he lived out the remainder of his days. His personal library and literary work were bequeathed to the Méjanes Library in Aix-en-Provence.