Montcalm's first blow against the English was struck in August, 1756, six months before the attack on Fort William Henry, which had been arranged by Vaudreuil. Three battalions of regular troops, with 700 Canadians and 250 Indians, with a strong force of artillery, were quietly concentrated at Fort Frontenac, and were intended for an attack upon the important English post of Oswego. Fighting had been going on in this neighbourhood for some time, and it was from Oswego that Shirley had intended to act against Niagara and Frontenac. That enterprise had fallen through, owing to Shirley having been deprived of the command; but a sharp fight had taken place between Colonel Bradstreet and his armed boatmen, and 1100 French, who were beaten off.
Oswego was a place of extreme importance. It was the only English post on Ontario, situated as it was towards the southwest corner of the lake. So long as it remained in their possession, it was a standing menace against the whole line of communications of the French with the south. Owing to gross neglect, the fort had never been placed in a really defensive condition. The garrison was small, and crippled with the fever, which had carried off great numbers of them. The remainder were ill fed and discontented.
On the 12th of August, the Earl of London sent Colonel Webb, with the 44th Regiment and some of Bradstreet's boatmen, to reinforce Oswego. They should have started a month before, and, had they done so, would have been in time; but confusion and misunderstanding had arisen from a change in command. Webb had scarcely made half his march, when tidings of the disaster met him, and he at once fell back with the greatest precipitation.
At midnight on the 10th, Montcalm had landed his force within half a league of the first English fort. Four cannon were at once landed, and a battery thrown up, and so careless of danger were the garrison, that it was not till the morning that the invaders were discovered. Two armed vessels at once sailed down to cannonade them; but their light guns were no match for the heavy artillery of the French, and they were forced to retire.
The attack was commenced without delay. The Indians and Canadians, swarming in the forest round the fort, kept up a hot fire upon it. By nightfall the first parallel was marked out at 180 yards from the rampart.
Fort Ontario, considered the strongest of the three forts at Oswego, stood on a high plateau on the right side of the river, where it entered the lake. It was in the shape of a star, and formed of a palisade of trunks of trees set upright in the ground, hewn flat on both sides, and closely fitted together--an excellent defence against musketry, but worthless against artillery. The garrison of the fort, 370 in number, had eight small cannon and a mortar, with which, all next day, they kept up a brisk fire against the battery which the French were throwing up, and arming with twenty-six pieces of heavy artillery.
Colonel Mercer, the commandant of Oswego, saw at once that the French artillery would, as soon as they opened fire, blow the stockade into pieces, and thinking it better to lose the fort, alone, than the fort and its garrison, he sent boats across the river after nightfall, and the garrison, having spiked their guns, and thrown their ammunition into the well, crossed the river, unperceived by the French.
But Oswego was in no position for defence. Fort Pepperell stood on the mouth of the river, facing Fort Ontario. Towards the west and south the place was protected by an outer line of earthworks, mounted with cannon, but the side facing the river was wholly exposed, in the belief that Fort Ontario would prevent any attack in this direction.
Montcalm lost no time. The next evening, his whole force set to work throwing up a battery, at the edge of the rising ground on which Fort Ontario stood, and, by daybreak, twenty heavy guns were in position, and at once opened fire. The grape and round shot swept the English position, smashing down the mud-built walls, crashing through the stockades, and carrying destruction among the troops. The latter made a shelter of pork barrels, three high and three deep, and planted cannon behind them, and returned the enemy's fire; but the Canadians and Indians had crossed the river, by a ford two miles up, and soon opened fire from all sides.
Colonel Mercer, who had bravely led his men, and inspired them by his example, was cut in two by a cannon shot, and the garrison were seized with despair. A council of officers was held, and the garrison surrendered as prisoners of war, to the number of sixteen hundred, which included sick, the sailors belonging to the shipping, labourers, and upwards of a hundred women.