Mekhitar da Pietro, known as Abbot Mekhitar, also spelled Mkhitar, (in Armenian Մխիթար Սեբաստացի Mxit'ar Sebastaci meaning Mekhitar of Sebaste) born Petros Manuk (Manouk Petrosian) (1676-1749) was an Armenian Catholic monk (convert from Armenian Orthodox) and a prominent scholar and theologian (see Vardapet) who founded what would become the Mekhitarist Order.
Born Petros Manuk (Peter of Manug) in Sivas (Sebaste) in Anatolia on 7 February 1676, he entered the Surp Nshan (Holy Cross) monastery, taking the name Mekhitar ("The Consoler"). In 1696 he was ordained a priest.
Inspired by the idea of creating an order of preachers dedicated to raising the educational and spiritual level of the Armenian people, Mekhitar founded in 1701 in Constantinople what would become known after his death as the Mekhitarist Order.
Two years later, escaping persecution, the order moved to Modone in the Peloponnese, then known as the Morea, which was a Venetian possession. In 1715, the order moved to the Island of San Lazzaro degli Armeni at the invitation of the Venetian Republic. Mekhitar built up the monastery on the island and the order which sent out priests to serve Armenian communities in the Middle East.
Mekhitar died at the monastery on 27 April 1749 and is buried in the monastery church.