structural:summarization
Facing Napoleon

On 26 February 1815, Napoleon escaped from Elba and returned to France. He regained control of the country by May and faced a renewed alliance against him. Wellington left Vienna for what became known as the Waterloo Campaign. He arrived in the Netherlands to take command of the British-German army and their allied Dutch, all stationed alongside the Prussian forces of Generalfeldmarschall Gebhard Leberecht von Blücher.

Napoleon's strategy was to isolate the Allied and Prussian armies and annihilate each one separately before the Austrians and Russians arrived. In doing so the vast superiority in numbers of the Coalition would be greatly diminished. He would then seek the possibility of peace with Austria and Russia.

The French invaded the Netherlands, with Napoleon defeating the Prussians at Ligny, and Marshal Ney engaging indecisively with Wellington at the Battle of Quatre Bras. The Prussians retreated 18 miles north to Wavre whilst Wellington's Anglo-Allied army withdrew 15 miles north to a site he had noted the previous year as favourable for a battle: the north ridge of a shallow valley on the Brussels road, just south of the small town of Waterloo. On 17 June there was torrential rain, which severely hampered movement. and had a considerable effect the next day, 18 June, when the Battle of Waterloo was fought. This was the first time Wellington had encountered Napoleon; he commanded an Anglo-Dutch-German army that consisted of approximately 73,000 troops, 26,000 of whom were British. Approximately 30 percent of that 26,000 were Irish.