From the AHD:

Enthusiasm first appeared in English in 1603 with the meaning “possession by a god.” The source of the word is the Greek enthousiasmos, which ultimately comes from the adjective entheos, “having the god within,” formed from en, “in, within,” and theos, “god.”

http://www.bartleby.com/61/14/E0161400.html

Bingley

Bingley