I'm currently doing research on the Napoleonic wars, and I've heard the claim that the Rothschilds made their fortune by falsely claiming that Napoleon won so that the British would sell their stocks, only for the family to buy all of it and leave England broke, thus forcing them to rely on the national bank now owned by the Rothschilds to make ends meet. Are there any reliable sources on this? Or this is all conspiracy talk?
More can always be said, but u/mikedash gave a comprehensive answer to that question a few years ago. (edit: corrected the name of the person who answered)