Slavery in pagan times versus Christian times

From Bulfinch's Age of Fables:

"In memory of his [Saturn's] beneficent dominion, the feast of Saturnalia was held every year in the winter season. Then all public business was suspended, declaration of war and criminals executions were postponed, friends made presents to one another, and the slaves were indulged with great liberties. A feast was given them at which they sat at table, while their masters served them, to show the natural equality of men, and that all things belonged equally to all, in the reign of Saturn."


While I can't research further or write about it tonight, I read this and wanted to note that slavery appears to have been worse in America than in pagan Europe, as far as the dignity of the slave is concerned. There are probably various reasons for this, and there were obviously differences in harshness of practice both throughout Europe and America, depending on local custom, the individual slaveowner, etc. Nonetheless, I know of no such ritual in America where slaves were put ahead of their masters.

And slavery was in fact on the decline in Christian Europe from the fall of Rome until at least the end of the Middle Ages. Why did at least the first 1000 years of Christianity see a drastic reduction in slavery in Europe, only to see its revival later on? I'm sure empire had to do with it. But I suspect many undercurrents of thought helped contribute to desiring empire and exploration, so that's too simple an explanation.

And I don't think anyone back then had a concept of race, so racial inferiority couldn't have been a justification for changing opinions on the universal equality of men that was held even by the pagans and would have found a fuller defense in the Christian tradition.