When did Napoleon turn from a villain to a hero?

by lesliecoin

Most people in Russia, Britain etc hated Napoleon during his reign. He was a tyrant, but now we enjoy cakes named after him. When and why did the attitude towards him change?

voyeur324

/u/DonaldFDraper has previously answered the related questions of 'Was Napoleon good or bad?' and Why is there so much hostility and controversy surrounding Napoleon?