If you scroll down on the Lead Adventure thread at the link, you will find a simple set of free wargames rules and a skirmish scenario for Late Roman “Pulp” Adventure.
Rules: Ancients
Gladius and Pilum Ancients Rules
Gladius and Pilum is a set of free wargames rules for battles set in the 500BC to 500AD era. They’re designed for 15mm miniatures, with one figure equaling 50 men.
By The Gods Ancients Warfare Rules
By The Gods is a set of free wargames rules for ancients warfare. The rules are relatively uncomplicated, but do have some modifications for “national characteristics.”
Bronzed Heroes Classical Warfare Skirmish Rules
Bronzed Warfare is a set of free wargames rules for skirmishes in the classical bronze age.
Death On The Seas Ancient Naval Rules
Death on the Seas is a set of free wargames rules for ancient naval warfare. Also, Death On The Seas ship appendix.