The History of Dumas' Musketeers--a personal webpage created by Jerry Stratton (I won't vouch for the correctness of the site, but you might want to investigate these topics for yourself)
The Three Musketeers (1921)
The Three Musketeers (1973/74)
The Four Musketeers (1973/74)
The Three Musketeers (1993)