In 1829, as part of John Jacob Astor’s American Fur Company plan to extend trading into the Upper Missouri country, Fort Union was built near the junction of the Missouri and Yellowstone Rivers after early explorers reported that America’s western mountains were rich in furs. The post soon became the headquarters for trading beaver furs and buffalo robes with the Assiniboin Indians to the north, the Crow Indians on the upper Yellowstone, and the Blackfeet farther up the Missouri. In its heyday, the fort was a busy place that employed up to 100 people, with a bourgeois, or manager, directing its operations and the work of traders and craftsmen. During its thirty-eight years of operation, travelers and famed men passed through its gates, including adventurers, artists, scientists, priests, and even princes, making it one of the busiest and grandest fur trading outposts reached by river travelers in the 1830’s.