What religions and intellectual developments led some Europeans and some Americans to question and criticize the institution of slavery?

Answer 1

The religious and intellectual developments that led some Europeans and some American to question and criticize the institution of slavery were the crusades and the Enlightenment and Revolution. The eighteenth century crusade against slavery originated from the changes in religious and intellectual outlooks on slavery among small but influential groups in both America and Europe. The Enlightenment questioned the wisdom of having existing institutions that it chewed away at older defenses of slavery (mostly the unchanging social hierarchy). The general Enlightenment rhetoric of equality stood in sharp contrast to the radical inequality of slavery.