In December of 1804, as temperatures fell below freezing and snow began to fall, the Corps of Discovery continued finishing Fort Mandan, hunting, and gathering firewood while the captains carried on diplomatic, scientific, and mapmaking work. Natural history specimens were collected, documented, and packaged for shipment back to President Jefferson, and Meriwether Lewis treated many cold-related ailments among Corps members and their Mandan and Hidatsa neighbors. When severe weather forced people indoors, the explorers and their Mandan and Hidatsa neighbors bonded, formed lasting friendships, and cultivated trust that eventually led Mandan Chief Shehdke-shote and his family down the Missouri in the spring of 1806 and on to the nation's capital. During the winter at Fort Mandan, the Corps became a more cohesive unit, and under the competent leadership of Lewis and Clark and in anticipation of the mission ahead, the season produced what William Clark called a "perfect harmony."