Upon Napoleon's return from Elba, his mercurial brother-in-law, the King of Naples, Joachim Murat, offered the Emperor his services once more for the expected campaign of 1815. Napoleon rebuffed Murat's offer and met his Waterloo, while Murat ended up facing a Neapolitan firing squad.
My question for the forum, (purely speculative in nature, of course) is what would have happened if Napoleon had crossed the Belgian border in June, 1815 with Murat, arguably one of the greatest commanders of horse in history, leading his cavalry? Would the result have been different on June 18? Instead of Ney (ironically a cavalryman himself) mishandling the situation, would Wellington's army have been broken by the master leader of cavalry himself in an exploit even greater than his legendary charge at Eylau? Also, would Murat's presence have changed any other aspects of the campaign, most especially the outcomes at either Ligny or Quatre Bras?