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 under the command of General Johann von Thielmann 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 at Waterloo.