I heard it mentioned on the TV the other night that "condom" came from the name of an English nobleman who invented the modern device in the 19th century...Sir John Condom, or something like that. However, I couldn't find anything about that in Googling. But, I found this...seems "condom" is another "origin unknown" mystery akin to "the whole nine yards' or "the full monty". But, here, the threadmaster likes the Italian origin:

http://www.wordwizard.com/clubhouse/founddiscuss.asp?Num=3004