there were some movements considered heresies by the early church which do not exist today and are not generally referred to as denominations. examples include the gnostics (who had believed in an esoteric dualism), the ebionites (who venerated christ's blood relatives), and the arians. the greatest divisions in christianity today, however, are between eastern orthodoxy, roman catholicism, and various denominations formed during and after the protestant reformation. there also exists in protestantism and orthodoxy various degrees of unity and division.