During the initial stages of the war, Major-General Isaac Brock moblized contingents of Upper Canada militia, including Essex, Kent, Norfolk and Oxford from the western districts, to bolster his forces in the face of a large American invasion force being assembled in the Michigan territory under the command of Brigadier-General William Hull. Though out numbered, this combined force of regulars and militia was successful in capturing Detroit in August 1812. Elements of the Essex militia were also actively engaged at the Battle of Frenchtown in January 1813 and at the Siege of Fort Meigs in May 1813.