Fort Plain, also known as Fort Rensselaer, was built in 1778-79 on a hilltop at Fort Plain as a strong strategic and defensive position, where families from nearby settlements retreated behind the stockade for protection from enemy raids. In the spring of 1781 it replaced Fort Stanwix as the western headquarters for defense of the Mohawk Valley under Colonel Marinus Willett. Archeological digs have confirmed the plan of the original 1779 fort. Willett expanded it in 1781 with a redoubt and new buildings to house as many as 600 troops, and in 1782 a new blockhouse designed by Major Jean de Villefranche was added to hold 200 men. General George Washington inspected the fort during a tour of the region in 1783. During the American Revolution, almost half of the military actions in New York State occurred along the strategic corridor of the Mohawk Valley. In 1777 British, Native American, and Loyalist battalions attacked from the west and north, but defeats at Fort Stanwix and elsewhere forced a British surrender at Saratoga, the war's turning point. The bloodshed at Oriskany in 1777 was one of many encounters between former neighbors on the battlefield. In this region the Revolution became a civil war that divided families and communities, both European and Native American. Many who remained loyal to the British king were forced to move and forfeit their property, while others took up arms or struggled to remain neutral. For seven years enemy raids terrorized the Mohawk Valley and periodically burned the fertile farms of New York's bread basket. By 1783 the region had been reduced to little more than fortified homesteads, militia posts, and abandoned fields.