Waterloo
The Battle of Waterloo was the final battle in the Napoleonic wars, fought in Waterloo, France, in 1815, between British forces and Napoleon. The defeat at Waterloo sent Napoleon into exile for the remainder of his life and effectively began an era of British world dominance. Mr. Parker's attention to Waterloo as the "thing now" suggests that the story is taking place shortly after the victory at Waterloo and British society continues to feel the triumph of Britain over France.
Video Recap: https://www.youtube.com/watch?v=nDZGL1xsqzs https://www.history.com/topics/british-history/battle-of-waterloo#section_5