The campaign involved land and naval forces of Great Britain and France, and land forces of the United States. British forces were sent to Virginia between January and April 1781 and joined with Cornwallis's army in May, which came north from an extended campaign through the southern states. These forces were first opposed weakly by Virginia militia, but General George Washington sent first Marquis de Lafayette and then "Mad" Anthony Wayne with Continental Army troops to oppose the raiding and economic havoc the British were wreaking. The combined American forces, however, were insufficient in number to oppose the combined British forces, and it was only after a series of controversially confusing orders by General Sir Henry Clinton, the British commander-in-chief, that Cornwallis moved to Yorktown in July and built a defensive position that was strong against the land forces he then faced, but was vulnerable to naval blockade and siege.