That December, General Nathanael Greene arrived with an army of Continental troops. When Greene heard of Tarleton's approach, he sent Brigadier General Daniel Morgan and his backwoodsmen over the Appalachian Mountains to stop him. On January 17, 1781, the two forces met at a grassy field with widespread hardwoods, reeds, and marsh in a well-known cattle grazing area called Cowpens. Pickens and his guerilla soldiers joined Morgan directly before the battle. Morgan still felt they were not strong enough to take on Tarleton's trained troops and wanted to cross a river that would separate them from the British and secure them a chance to retreat. Pickens convinced Morgan that staying on the British side of the river would force his men to fight it out in what some historians consider the best-planned battle of the entire war. The Patriots defeated the British and later battles at Hobkirk's Hill and Eutaw Springs would further weaken the British.