Century is a set of free wargames rules for playing ancients wargames set in the period 400BC to 150BC.
Rules: Ancients
Against the Scourge of God – Battle of Chalons
Against the Scourge of God is a set of rules and a scenario for replaying the battle of Chalons. At Chalons, Romans under Aetius and Visigoths under Theoderic turned back an invasion of the Huns.
Champs de Bataille Ancients Rules
Champs de Bataille is a set of free wargames rules for ancients based on DBM. Each unit represents 125 to 250 cavalry or foot; more if a warband. The game is designed to be played on a hex board.
Link (direct download)
Battle of Granicus
The Junior General offers a set of fast play rules as well as paper figures for the Battle of Granicus, in which Alexander The Great took on the Persian Empire.
Advanced Virtus Ancients Rules
Advanced Virtus is a set of free wargames rules for ancient warfare. They’re described as “fast and furious.”