Article: After the American Revolutionary War, the number and proportion of free people of color increased markedly in the North and the South as slaves were freed. Most northern states abolished slavery, sometimes, like New York, in programs of gradual emancipation that took more than two decades to be completed. The last slaves in New York were not freed until 1827. In connection with the Second Great Awakening, Quaker and Methodist preachers in the South urged slaveholders to free their slaves. Revolutionary ideals led many men to free their slaves, some by deed and others by will, so that from 1782 to 1810, the percentage of free people of color rose from less than one percent to nearly 10 percent of blacks in the South.

Now answer this question: What caused many slaveholder to free their slaves?
Revolutionary ideals led many men to free their slaves