<P> During the American Revolutionary War, the British troops occupied New York City in 1776 . The Crown promised freedom to slaves who left rebel masters, and thousands moved to the city for refuge with the British . By 1780, 10,000 black people lived in New York . Many were slaves who had escaped there from slaveholders in North and South . After the war, 3,000 slaves were evacuated with the British, most being taken to Nova Scotia for freedom . </P> <P> When Vermont asserted its independence from both New York and New Hampshire, it abolished slavery within its territory . </P> <P> After the American Revolution, the New York Manumission Society was founded in 1785 to work for the abolition of slavery and for aid to free blacks . The state passed a 1799 law for gradual abolition; after that date, children born to slave mothers were free but required to work for the mother's master for an extended period as indentured servants into their late twenties . Existing slaves kept their status . All remaining slaves were finally freed on July 4, 1827 . </P> <P> Chattel slavery in the geographical area of the present - day U.S. state of New York began in 1626, when 11 Africans were unloaded into New Amsterdam harbor from a ship of the Dutch West India Company . Before this time, the company had tried to encourage Dutch agricultural laborers to immigrate to and populate New Netherlands . This experiment was unsuccessful, as most immigrants wanted to accrue greater income in the lucrative fur trade and return to their home country in luxury . </P>

When was slavery outlawed in new york state