“Neither did the Western Church, as far as I know, oppose slavery actively, but I am not discounting brave efforts by some individuals as a distinct but ineffective possibility. I am simply not aware of any prominent opposition to slavery in either the East or the West.”
Jefferson Davis, a High Church Episcopalian, had a Catholic education and was on friendly personal terms with the Pope. In fact, when Davis was imprisoned under very harsh conditions after the WBTS, the Pope personally handcrafted a Crown of Thorns and sent it to him.
How does that relate to opposing slavery?