Marshall Blucher was a veteran of many of the European wars fought in the late 18th and early 19th century, indeed he had fifty fears of military service behind him by the time Waterloo was fought. Prior to the Napoleonic Wars the Prussians had a high military reputation mainly because of the astonishing victories of Frederick the Great. However the French once they recovered from the revolutionary turmoil became masters of mainland Europe.
Blucher was a Prussian military commander of the old school and had lived through some of his country’s biggest successes not to mention worst defeats, in particular the savage mauling at Jena in 1806. That shattering defeat had led to the restructuring of the Prussian army and a subservient role to France.
Blucher had played a prominent role in the campaigns against France in 1813 – 14 that led to the abdication of Napoleon and the restoration of the Bourbon monarchy. The Prussian victory at Leipzig was crucial to weakening the French. However the following year the erstwhile Emperor returned for 100 days after escaping from exile.
Alongside Wellington he was tasked with defeating the French.
Unfortunately the Prussians were not linked to the British /
Dutch / Hanoverian forces and Napoleon intended to defeat them
separately. The Prussians were defeated at Ligney on 16 June yet the
French did not stop them reaching Waterloo two days later. The late
arrival of the Prussians completed the defeat of the French already
badly mauled by Wellington's forces. Blucher and his forces were the
straw, which broke the camel's back.