approved black leaders as preachers; blacks developed their own strain of Christianity. Before the American Revolutionary War of 1775–1783, few slaves were manumitted; on the eve of the American Revolution, there was an estimated 30,000 free African Americans in Colonial America which accounts for about 5% of the total African American population with most of free African Americans being mixed race. Since the portion of free African Americans were so small and could possibly pass as white, they were not deemed a threat to the White population to warrant anti-Black legislation. However, historian Ira Berlin states that this figure could be as high as 25% due to errors in census collection, ambiguous status of runaway slaves, White-passing persons, and slaves who lived as if they were free but did not have the papers to prove the same. The war greatly disrupted slave societies. Beginning with the 1775 proclamation of Lord Dunmore, governor of Virginia, the British recruited slaves of American revolutionaries to their armed forces and promised them freedom in return. The Continental Army gradually also began to allow blacks to fight, giving them promises of freedom in return for their service. Tens of thousands of slaves escaped from plantations or from other venues during the war, especially in the South. Some joined British lines or disappeared in the disruption of war. After the war, when the British evacuated New York in November 1783, they transported more than 3,000 Black Loyalists and thousands of other American Loyalists to resettle in Nova Scotia and in what became Upper Canada (part of present-day Ontario). A total of more than 29,000 Loyalist refugees eventually departed from New York City alone. The British evacuated thousands of other slaves when they left Southern ports, resettling many in the Caribbean and others in England. In the first two decades after the war, the number and proportion of free Negroes in the United States rose dramatically: northern states abolished slavery, almost all gradually. But also many slave owners, in the Upper South especially, inspired by the war's ideals, manumitted their slaves. From 1790 to 1810, the proportion of free blacks in the Upper South rose from less than 1% to overall, and nationally, the proportion of free blacks among blacks rose to 13%. The spread of cotton cultivation in the Deep South drove up the demand for slaves after 1810, and the number of manumissions dropped after