The Siege of Fort William Henry was a part of the French and Indian War. In August 1757, French troops under Louis-Joseph de Montcalm and their Abenaki allies under the Assassin Kesegowaase besieged Fort William Henry for days, until the British commander, George Monro, surrendered.
Monro and his men were allowed to retreat, but despite Montcalm's orders, Kessegowaase and his Indian Allies disobeyed them and ambushed the fleeing British. Seeking to kill Monro, who was a member of the Templar Order and supposedly held the Precursor manuscript, he and his men killed dozens of British troops. Thanks to the intervention of Templar ally and former Assassin Shay Cormac, Monro survived.