The main reason he formed an alliance with the British during the War of 1812 was because he thought the Native Americans could gain land. Forming an alliance with the British was an attempt to resist white encroachment of Native lands and to restore Native ethics that had been deteriorating. To give context, in 1812, the United States had 7000 soldiers whereas Britain only had 24 388, meaning that the war was heavily in favor of the British. However, the tables were turned at the Battle of Thames in 1813 when the British and Native Americans were defeated by an American force. Tecumseh was killed, and the surviving Native Americans withdrew from the alliance. By that time, Tecumseh had taken over Detroit. Who was Tecumseh Tecumseh was a Shawnee Native American Shawnee chief, born in Circa 1768 south of present-day Columbus, Ohio. During the early 1800s and attempted to organize a confederation of tribes to resist white settlement.After years of watching social and cultural deterioration, intertribal conflict, and white encroachment on Native American landsc, Tecumseh, a young warrior, developed a plan. The only way that Native Americans could restore control over their lives, he said, was to unify. They needed to overcome their tribal differences restore there ethics and and unite as a people, and and make an alliance strong enough to defeat the military forces supporting white expansion.What was the war of 1812 The War of 1812 was an important conflict with lasting consequences, particularly for the native inhabitants of North America. During the years before the war, the United States wanted to expand its territories, a desire that fueled the invasion of native homelands throughout the interior of the continent. Tribal nations of the lower Great Lakes, including the Shawnee, Potawatomi, Ojibwa, and others saw their lands at risk. The War of 1812 lasted from June 1812-February 1815, a span of two years and eight months. Peace negotiations began in late 1814, but slow communication across the Atlantic (and indeed across the United States) prolonged the war and also led to numerous tactical errors for both sides.The same was true for the Muscogee Creek, Seminole, Choctaw, Cherokee and Chickasaw in the south.