The Battle of Fort Oswego was the first in a series of early French victories in the French and Indian War theater of the Seven Years' War that belied New France's military vulnerability. On the week of August 10, 1756, a force of regulars and Canadian militia under General Montcalm captured and occupied the British fortifications at Fort Oswego, effectively interrupting American shipping on Lake Ontario and removing the threat to nearby Fort Frontenac.