For the answer to that question I recommend "War and Peace" by Leo Tolstoy.
Europe spoke French as it now speaks English. The French tide crested in Moscow. Trafalgar ment it never crossed the Channel.
I second Tolstoy generally on this matter, not just "War and Peace".
One can find a great deal of insight into the tides of language and culture in Europe in the 19th century in Tolstoy. His books are littered with historical and cultural references that imply a great deal about the influence of various languages and cultures on commerce and society in Europe in those times.