The British had a plan to take over, New York so they can attack Boston and Massachusetts. But George Washington had 1/3 of his army that would fight there and defend New York, in the end, the colonist lost and almost lost the war there is not for Washington's retreat. Battles before this though had no black men free or not join the congressional army
Oct 17, 1777
when General Washington had crossed the Delaware River he did a sneak attack on British troops without even losing one man. Later in the battle of Princeton, they fight delayed troops. But before this, he had lost a good portion of his men to disease and other things, so with hesitation Washington let both slaves and free black people join the army some of which had been with Washington while he was crossing the Delaware River.
Oct 18 1777
Between Dec 25 and Jan 3, Washington noticed that the British troops are scattered and so help wound be delayed and so Washington and his men took position on Rambo Mountain. Not long after General Cornwallis had troops fighting all day on Jan 2, during the fight he noticed that there were fords near the creek and so his plan the next day was to corner them in the fords. Tho it didn't really work out because whil they fought Washington went around to Princeton.
After the battle at Hudson river, the french realized that the war was worth fighting in but beforehand on Oct 17 Hudson surrendered 5,000 or so troops after the battle that the colonist won after having less troops .
About 4,000 British and Hession troops tried to attack Washington at Pelham Manor but were met with 700 of Washington's men and a heavy attack.