Early on Sunday 18th June 1815 the 68,000 men of Wellington’s Anglo-Dutch army took up positions, after a wet and miserable night, along a crescent-shaped ridge to the south of Mont St Jean. Wellington had chosen the ground with care to ensure that he had the advantage of shelter from French artillery fire, although his line was by on means impregnable. The bulk of his forces were deployed to cover his centre, marked by a crossroads just to the north of La Haye Sainte, and right, where the ridge curved south towards the chateau and farm of Hougoumont. His left, towards Papelotte and La Haye, was less strongly defended, although Wellington hoped that the gap would be filled by Prussian troops, marching from the east under Marshal Blucher, as the day went on. Both La Haye Sainte and Hougoumont contained allied garrisons, partly to attract enemy attention but also to force the French to concentrate their main assault on the fairly narrow corridor between the two farms.
Facing the allies were about 72,000 Frenchmen under the overall command of Napoleon, the first time that he and Wellington had meet on the field of battle. The Emperor’s plan was to begin with a massive artillery barrage and an attack on Hougoumont, intended to force Wellington to commit his reserves to the defence of the chateau. This would weaken the allied centre preparatory to a major French infantry assault. Hougoumont was attacked at 11:30am and defended by British Foot Guards, was to be the scene of desperate fighting throughout the day, although the fact that it never fell to the French meant that Wellington’s right flank was secure.
The French artillery barrage began at about midday, inflicting terrible casualties on the allied infantry along the ridge. Ninety minutes later, four French infantry divisions started to advance in a line that stretched from La Haye Sainte to Papelotte. They were met by allied artillery fire and the disciplined volleys of the 5th Division, followed by a cavalry charge carried out by the Household and Union Brigades.
By 3pm the immediate threat to Wellington’s centre had passed, although an hour later British infantry were presented with the amazing sight of nearly 4,000 French horsemen coming towards them. The infantry immediately ‘formed square’ to create solid fortresses out of which musket fire could be poured to disrupt and cavalry charge. Protected by artillery, none of the squares was broken and, as French casualties mounted, the cavalry withdrew. Elsewhere, however, the French did enjoy success, taking La Haye Sainte when the defenders ran out of ammunition. This persuaded Napoleon that the allies were cracking.
At 6pm he ordered his remaining reserve (seven battalions of the Imperial Guard) to advance across ground to the right of Hougoumont. They did so with superb discipline, despite coming under intense artillery fire, but as they approached the ridge they encountered British infantry that had been sheltering on the reserve slope. As volley after volley poured into the French ranks, the Imperial Guard faltered and broke. Wellington, aware by now that the Prussians had arrived to cover his left flank, signalled his forces to advance. They proceeded to sweep the enemy from the field.
The battle, in Wellington’s own words, was ‘the nearest run thing you ever saw in your life’, but it was decisive. At a cost to the allies of about 22,000 casualties, Napoleon’s dream of a restored empire lay shattered.