Hi TMC,
i think like other institutions over a 2000 year period you can point to areas where slavery was practiced, if not theologically supported.
But what i think is clear is that the general trajectory of the Church’s position is against slavery. Whether it be Paul’s letter to Philimon describing himself as a ‘prisoner of Christ’ and asking him to take his slave Timothy back as ‘a brother’, or the fact that Christianity was known as the ‘religion of slaves’ or that many of the first popes were former slaves, there was a Christian relationship with slavery which did not support exploitation.
When Christianity became the state religion of Rome slavery was ended shortly after. When the European Christian people converted the Vikings then slavery ended in much of Western and Northern Europe.
With the European interactions with the Muslim invasions and slave taking of Europe then many European kingdoms undertook slavery to overseas possessions. But Christians again stopped slavery in these lands through people on the ground and from home European countries who became aware of what was going on in the overseas possessions. What was a major transformation across the whole globe though was that Christians not only ended slavery (again) in their lands but at great financial and human cost stopped slavery all over the planet.
What is interesting to me is that the ending of slavery on the planet was a major social transformation but our kids are not taught how it ended, not just in one country but across the planet.
youtube.com/watch?v=ao7FKReHYKY