Aftermath
Wellington and Blucher meet at La Belle Alliance
Across the battlefield, several French units offered isolated resistance but were soon overwhelmed. The pursuit of the French army was entrusted to the Prussians. Wellington and Blucher famously met and embraced at La Belle Alliance.
Losses
Losses on the day were horrendous. On a battlefield measuring only 4 miles by 2 miles, and during an 8-hour period from the first attack on Hougoumont to the final retreat of the Old Guard, casualties amounted to 25,000 French and 22,000 Allies. As Wellington commented, 'I don't know what it is to lose a battle, but certainly nothing can be more painful than to gain one with the loss of so many of one's friends.'
Result
Perhaps the main result of the battle was that support for Napoleon died away and he abdicated on 22nd June. Paris surrendered on 4th July and was occupied by the Allies, ending more than 20 years of war. Napoleon himself was exiled to St Helena, 1200 miles off the west coast of Africa, where he stayed until his death in 1821.
Assessment
The Battle of Waterloo has been debated time and again by historians. Did Wellington secure victory as a result of his own skill as a defensive commander or as a result of the mistakes made by Napoleon? It is clear that Napoleon was not at the height of his powers and seems to have displayed little of the drive and audacity that spectacularly won him victory at Austerlitz. His initial appointment of generals was unwise, he launched a frontal attack rather than a flanking manoeuvre, he allowed Ney to take control at the crucial point in the battle, he hesitated to commit his Old Guard and he failed to communicate the importance of the pursuit to Grouchy. However, it would be unfair to deny Wellington any credit. He organised a heterogeneous collection of multinational troops into a cohesive fighting force, he moulded a close relationship with Blucher despite mutual incomprehension (a relationship upon which the outcome of the campaign depended), he chose a useful (though not ideal) defensive position from which to receive Napoleon's attack and he always seemed to be on hand throughout the day at the most crucial points on the battlefield to deal personally with potential crises.
Perhaps the biggest mistake made by Napoleon at Waterloo was to underestimate his opponent.