After the rout of American forces at Bladensburg and the burning of Washington, D.C., the British expeditionary force under Maj. Gen. Robert Ross turned its sights northward to Baltimore, Maryland. However, Baltimore had been preparing for such an assault for more than a year now; its citizens and militia built defenses around the city. The imposing Fort McHenry, at the mouth of the inner harbor, provided the linchpin for the American defenses. General Ross landed his British forces east of the city in preparation for a land assault. The Maryland militiamen under Brig. Gen. John Stricker inflicted serious casualties on the regulars and killed Ross in a delaying action that culminated with the Americans retreating back into the city. The next day, another confrontation between the British regulars and American militiamen resulted in the British command having to resort to naval support to take the city. The fall of Fort McHenry was vital to the British plan, as the British Navy could not properly assist the land forces. However, Fort McHenry withstood the twenty-seven hours of bombardment, an event that would inspire Francis Scott Key to write the poem that would eventually become "The Star-Spangled Banner." The British fleet soon withdrew, ending their invasion of the Chesapeake.