MARCOSIANS, or COLOBARIANS, an ancient sect in the church, making a branch of the VALENTINIANS.
St Irenæus speaks at large of the leader of this sect, Marcus, who it seems was reputed a great magician. The Marcosiars had many apocryphal books which they held for canonical, and out of which they picked several idle fables touching the infancy of Jesus Christ. Many of these fables are still in use and credit among the Greek monks.