The opening shots of the War of 1812 were fired in the vicinity of the fort's future site, the "sand hill at Springwells". Although war had not yet been officially declared, Michigan militiamen bombarded the town of Sandwich, Upper Canada (later annexed into Windsor), on July 4, 1812. Later in the course of the war, British general Isaac Brock crossed the narrowest part of the Detroit River with his troops and landed on the future Fort Wayne site before marching to Detroit. In the ensuing Siege of Detroit, American general William Hull, believing himself completely surrounded and outnumbered, surrendered Fort Shelby to the British without offering any resistance. The British later abandoned the fort and American troops reoccupied it. In 1815, the future Fort Wayne site was where American government and the local Native American tribal leaders met to sign the Treaty of Springwells, which marked the end of hostilities between the government and tribes who had allied with the British during the war. Among those present for the signing of the treaty were territorial governor Lewis Cass and General William Henry Harrison.