These rules are designed for playing games set in the period from c. 500 B.C. to c. 700 A.D. They use an alternate movement system and whole figure casualty removal. They are primarily designed for use with 15 and 25mm figures.
http://www.joomla.lancashiregames.com/joomla/index.php/free-rules/26-free-rules-by-dave-wareham/ancients