Complex sentence: Following the capture of Fort William Henry, the Marquis de Montcalm agreed to let the British withdraw with full honours of war-a civility that was not understood by some Indians who massacred the British and their camp followers on their way to Fort Edward.
Split into simpler sentences: Following the capture of Fort William Henry, the Marquis de Montcalm agreed to let the British withdraw with full honours of war. A civility that was not understood by some Indians who massacred the British and their camp followers on their way to Fort Edward.