Slavery seems to have been around in different configurations for a lot of human history. I know that it often wasn't as brutal and dehumanizing as the form it often took in the American South or the Caribbean during the plantation era.
However, no matter what form it took, it was still around--a person who was property of another person, who had no right to refuse to do work, and who was not compensated for his or her work.
I know a little about the British and French abolition movements that sprang up in response to the Transatlantic slave trade. But what about earlier such movements? Who spoke up against the ownership of human beings prior to, say, 1650? Who spoke against slavery in places other than Europe?
Thank you.
Ancient history really isn't my specialism, but I'm aware that the Persian (Achaemenid) Empire outlawed slavery, at least technically if not in practice. Furthermore, Persia was Zoroastrian which forbids the practice of slavery. More recently, I know there were plenty in Europe who voiced opposition to slavery in the early modern period. Gerrard Winstanely comes to mind, who set up a number of agrarian communes during the English Civil in which slavery was banned.
Gregory of Nyssa is probably the first reasonably explicit abolitionist - there are others before him who argue about details about slavery (Eustathius for example, who probably influenced him), and there are others who manumitted, but he's the first one to argue against owning another person outright and the institution of slavery (you'll want his 4th homily on Ecclesiastes).
There's a bit of an academic discussion as to whether he meant this as simply rhetoric or whether he was actually calling for abolition, but it tends to be the latter interpretation which wins out.