Napoleon
The popular name for the twenty Frane gold coin, struck by Napoleon I, from 1805 to 1815.
Conf. also Masson, Napoleon et les Femmes , 1894 (p. 103), where the piece of forty Franes issued by the same emperor is called a double Napoleon.
Source: Frey's Dictionary (American Journal of Numismatics, Vol. 50, 1916)