The Iroquois joined the British and attacked Pennsylvania and New England. Washington ordered a devastating attack on the natives in retaliation. The British convincingly entered Charlestown and dominated the southern colonies. The French entered the war on the side of the Americans. Washington ordered the fresh French troops to the south to launch a sea attack while his troops attacked by land. The team-up surrounded Yorktown, trapped the British and cut them off from northern re-enforcments. The British surrendered on October 19 1781. Once the treaty was official, Independance for the new nation was secured and the British troops were escorted out of the country, Washington disbanded his army and resigned as commander-in-chief.