There are 2 rules with this name.
This is a game to recreate the Battle of Hastings, fought on October 14th, 1066. The tabletop represents the battlefield of Hastings (Senlac Hill).
http://web.archive.org/web/20060829155319/http://www.angelfire.com/wa/rogerswhome/rules/medieval/BattleOfhastings.pdf
Fast Play Rules for Students.
http://www.juniorgeneral.org/hastings/hastings.html