In March 1778 Kościuszko arrived at West Point, New York, and spent more than two years strengthening the fortifications and improving the stronghold's defences. It was these defences that the American General Benedict Arnold subsequently attempted to surrender to the British when he defected. Soon after Kościuszko finished fortifying West Point, in August 1780, General George Washington granted Kościuszko's request to transfer to combat duty with the Southern Army. Kościuszko's West Point fortifications were widely praised as innovative for the time.