Complex sentence: In Christianity, worship of any other deity besides the Trinity was deemed heretical, but veneration for Mary, the mother of Jesus Christ, as an especially privileged saint--though not as a deity--has continued since the beginning of the Catholic faith.
Split into simpler sentences: In Christianity, worship of any other deity besides the Trinity was deemed heretical. The veneration of Mary, the mother of Jesus Christ, as an especially privileged saint--though not as a deity--has continued since the beginning of the Catholic faith.