Clinton returned in 1780 with 14,000 soldiers. American General Benjamin Lincoln was trapped and surrendered his entire 5400 men force after a long fight, and the Siege of Charleston was the greatest American defeat of the war (see Henry Clinton "Commander in Chief" section for more). Making the capture of Charlestown their chief priority, the British sent Gen. Clinton south from New England in October 1779. Gen. Lincoln was aware of the attack and set about fortifying the city, but an outbreak of smallpox over the winter was used by local slaveholders to excuse themselves from sending men to assist the effort. After reinforcement, Gen. Clinton approached the town via James Island and began his siege on April 1, 1780, with about 14,000 troops and 90 ships. Bombardment began on March 11. De Laumoy advised Gen. Lincoln's surrender, as the rebels had only about 5500 men and inadequate fortifications to repel the forces against them. As the British cut his supply lines and lines of retreat through skirmishes at Monck's Corner and Lenud's Ferry, Lincoln held out until May 12, when his surrender became the greatest American defeat of the war. Gen. Clinton left Lt. Gen. Charles Cornwallis in Charleston with around 3000 troops to consolidate British control and then move north against Virginia. These troops were responsible for Cornwallis's decisive victory at Camden on August 16.