A sect of ancient heretics towards the close of the second century; so called from Marcellus of Ancyra, their leader, who was accused of reviving the errors of Sabellius. Some, however, are of opinion that Marcellus was orthodox, and that they were his enemies the Arians, who fathered their errors upon him. St. Epiphanius observes, that there was a great deal of dispute with regard to the real tenets of Marcellus; but as to his followers, it is evident that they did not own the three hypostases; for Marcellus considered the Son and Holy Ghost as two emanations from the divine nature, which, after performing their respective offices, were to return again into the substance of the Father; and this opinion is altogether incompatible with the belief of three distinct persons of the Godhead.