In 1810, Manuel Lisa of the Missouri Fur Co. sent a large party of 32 trappers under Pierre Menard and Andrew Henry to establish a post at the Headwaters. Arriving on April 3, 1810, they built a small enclosure consisting of a fort and trading house at the Forks between the Jefferson and Madison Rivers. They accumulated large numbers of beaver, but grizzly bears and Blackfeet killed several trappers, including George Drouillard, the Shawnee half-breed admired by Lewis and Clark for his wilderness skills. Menard concluded that it was hopeless to maintain a post at the Three Forks, and in the fall of 1810 the trappers abandoned the attempt to establish a permanent trading post at the Headwaters.