Which French marshal left Napoleon Bonaparte's command in 1810 to later become King of Sweden and Norway?

I really recommen a book by Annemarie Selinko called Désirée. It's a story of Napoleon's first love who later married Bernadotte and became 1st queen of Sweden and Norway. It's quite historically accurate and the reason I knew the answer

Anya, me, too!

Rraine, I read Desiree when I was about 15. 55years ago. Loved it. There is also a film starring Marlon Brando as Napoleon, Jean Simmons as Desiree, and Michael Rennie as Bernadotte.