Battle of Wavre
The Battle of Wavre was the final major military action of the Hundred Days campaign and the Napoleonic Wars. It was fought on 18–19 June 1815 between the Prussian rearguard, consisting of the Prussian III Corps under the command of General Johann von Thielmann (whose chief-of-staff was Carl von Clausewitz) and three corps of the French army under the command of Marshal Grouchy. A blocking action, this battle kept 33,000 French soldiers from reaching the Battle of Waterloo and so helped in the defeat of Napoleon at Waterloo.