Meanwhile, British Major General Isaac Brock was in York, the provincial capital, dealing with the unwilling Legislative Assembly and mobilizing the province's militia. He had only a single regiment of regulars and some small detachments of veterans and artillery to support the militia, but he was aware that there was no immediate threat from the disorganized and badly supplied American forces on the Niagara River, or from the lethargic American commander in chief, Major General Henry Dearborn at Albany, New York. Hull's army alone was occupying or threatening Canadian territory. Late in July, Brock learned of the capture of Mackinac. He was also informed by Lieutenant General George Prevost, the Governor General of Canada, that an additional regiment was being dispatched to Upper Canada, although as piecemeal detachments. Brock dispatched 50 of his small force of regulars and 250 volunteers from the militia westward from York to reinforce Amherstburg. On 5 August, he prorogued the assembly and set out himself after them. He and his force sailed from Port Dover, Ontario in batteaux and open boats. They reached Amherstburg on 13 August, at the same time as 200 additional Indian warriors who joined Tecumseh (100 "Western Indians" from Mackinac and 100 Wyandots).