How do I convince Charlemagne to accept his crown?

Hint 1 of 14:

You can't put on a magic show in front of him as a miracle.

Hint 2 of 14:

You'll need to create a more subtle miracle for him to see.

Hint 3 of 14:

You need to visit Peking, 1940 AD.

Hint 4 of 14:

Step out into the street and watch the fighting for a while.

Hint 5 of 14:

Take the Molotov cocktail that fails to explode.