Battle of Waterloo: It mainly sets off the social background at that time, which leads to the following. At the Battle of Waterloo, Thenardier "saved" (it should be said that he robbed the property of the deceased) Marius' father. Only then did Marius finally find Thenardier and repay him. This is the following bizarre story.
Marius' political thought only changed when he walked into the ABC cafe.