American Fur Company from having to compete with the Canadian and British companies, particularly along the borders around the Great Lakes and in the West. The AFC competed fiercely among American companies to establish a monopoly in the Great Lakes region and the Midwest. In the 1820s the AFC expanded its monopoly into the Great Plains and the Rocky Mountains, dominating the fur trade in what became Montana by the mid-1830s. To achieve control of the industry, the company bought out or beat out many smaller competitors, like the Rocky Mountain Fur Company. By 1830, the AFC had nearly complete control of the fur trade in the United States. The company's time at the top of America's business world was short-lived. Sensing the eventual decline of fur's popularity in fashion, John Jacob Astor withdrew from the company in 1834. The company split into smaller entities like the Pacific Fur Company. The Northern Division of the midwestern outfit continued to be called the American Fur Company and was led by Ramsay Crooks. To cut down on expenses, it began closing many of its trading posts. Decline Through the 1830s, competition began to resurface. At the same time, the availability of furs in the Midwest declined. During this period, the Hudson's Bay Company began an effort to destroy the American fur companies from its Columbia District headquarters at Fort Vancouver. By depleting furs in the Snake River country and underselling the American Fur Company at the annual Rocky Mountain Rendezvous, the HBC effectively ruined American fur trading efforts in the Rocky Mountains. By the 1840s, silk was replacing fur for hats as the clothing fashion in Europe. The company was unable to cope with all these factors. Despite efforts to increase profits by diversifying into other industries like lead mining, the American Fur Company folded. The assets of the company were split into several smaller operations, most of which failed by the 1850s. In 1834, John Jacob Astor sold his interest on the river to replace the old fur company. He invested his fortune in real estate on Manhattan Island, New York, and became the wealthiest man in America. After 1840, the business of the American Fur Company declined. Influence During its heyday, the American Fur Company was one of the largest enterprises in the United States and held a total monopoly of the lucrative fur trade in the young nation by