The siege of Charleston was a major engagement and major British victory, fought between March 29 to May 12, 1780, during the American Revolutionary War. The British, following the collapse of their northern strategy in late 1777 and their withdrawal from Philadelphia in 1778, shifted their focus to the American Southern Colonies. After approximately six weeks of siege, Major General Benjamin Lincoln, commanding the Charleston garrison, surrendered his forces to the British. It was one of the worst American defeats of the war.