The British Army forces present at Yorktown arrived in Virginia in four separate detachments. The first was sent from New York City in December 1780 under the command of the turncoat Brigadier General Benedict Arnold. The second was sent from New York in March 1781 under the command of Major General William Phillips to reinforce Arnold after a Franco-American threat. The third detachment to arrive was that of General Cornwallis, who had been active in the Carolinas and, following the Battle of Guilford Court House on March 15, decided to join forces with Arnold and Phillips. This was contrary to instructions from his superior, Lieutenant General Sir Henry Clinton, British Commander-in-Chief in North America. He arrived at Petersburg, Virginia in late May to take command of the troops there; Phillips had died of a fever just a week before, and Arnold returned to New York not long after Cornwallis arrived. While at Petersburg, Cornwallis was joined by a fourth detachment from New York that was under the command of the Hessian Colonel August von Voigt.