Meanwhile Dearborn, having first moved up from Plattsburg to Sackett’s Harbour, had attacked York on April 27 with the help of the new American flotilla on Lake Ontario.  This flotilla was under the personal orders of Commodore Chauncey, an excellent officer, who, in the previous September, had been promoted from superintendent of the New York Navy Yard to commander-in-chief on the Lakes.  As Chauncey’s forte was building and organization, he found full scope for his peculiar talents at Sackett’s Harbour.  He was also a good leader at sea and thus a formidable enemy for the British forces at York, where the third-rate Sheaffe was now in charge, and where Prevost had paved the way for a British defeat by allowing the establishment of an exposed navy yard instead of keeping all construction safe in Kingston.  Sheaffe began his mistakes by neglecting to mount some of his guns before Dearborn and Chauncey arrived, though he knew these American commanders might come at any moment, and though he also knew how important it was to save a new British vessel that was building at York, because the command of the lake might well depend upon her.  He then made another mistake by standing to fight in an untenable position against overwhelming odds.  He finally retreated with all the effective regulars left, less than two hundred, burning the ship and yard as he passed, and leaving behind three hundred militia to make their own terms with the enemy.  He met the light company of the 8th on its way up from Kingston and turned it back.  With this retreat he left the front for good and became a commandant of bases, a position often occupied by men whose failures are not bad enough for courts-martial and whose saving qualities are not good enough for any more appointments in the field.

The Americans lost over two hundred men by an explosion in a British battery at York just as Sheaffe was marching off.  Forty British had also been blown up in one of the forts a little while before.  Sheaffe appears to have been a slack inspector of powder-magazines.  But the Americans, who naturally suspected other things than slack inspection, thought a mine had been sprung on them after the fight was over.  They consequently swore revenge, burnt the parliament buildings, looted several private houses, and carried off books from the public library as well as plate from the church.  Chauncey, much to his credit, afterwards sent back all the books and plate he could recover.

Exactly a month later, on May 27, Chauncey and Dearborn appeared off Fort George, after a run back to Sackett’s Harbour in the meantime.  Vincent, Sheaffe’s successor in charge of Upper Canada, had only a thousand regulars and four hundred militia there.  Dearborn had more than four times as many men; and Perry, soon to become famous on Lake Erie, managed the naval part of landing them.  The American men-of-war brought the long, low, flat ground of Mississauga Point under an irresistible cross-fire while three thousand troops