Impetus is a set of wargaming rules that allows you to play battles from the Ancient, Medieval and Renaissance periods. It is produced by the same team that publish the Italian 'Dadi & Piombo' miniatures wargaming magazine.
It is an extremely flexible system which allows players to recreate armies from a huge period of history - from Ancient Egypt, Romans and the Crusades right through to the Hundred Years War and Samurai.
Impetus is designed to be played using miniatures in various scales: 6mm, 10mm, 15mm, 20mm, and 25/28mm are all catered for.
Miniatures are based in elements - 60mm wide for 6mm & 10mm, 80mm wide for 15mm, and 120mm wide for 20mm & 25/28mm. The depth of the element is stipulated, but is not vital. This enables you to play the system with armies already based for other games systems.
The game play is turn based, but is not traditional i-go/u-go. Players roll dice for initiative every turn, but units are able to react to enemy forces out of sequence.
Units have 3 or 4 statistics, the most important of which is VBU, a combination of unit strength and morale.
Combat is fast and simple. Units roll dice equivalent to their VBU in combat, with various modifiers giving bonuses to the number of dice thrown. Any score of '6' or double '5' score a hit. There is some record keeping required, as unit hits cause a reduction in VBU. When VBU is reduced to 0, the unit routs and is removed from the table.
Armies are points based, with average armies ranging between 300-500 points. There are 15 army lists detailed in the original rules, usually in 'matched pairs'. These include Alexander's Macedonians & Later Achaemedian Persians, 2nd Punic War Romans & Carthaginians, Gauls & Caesar's Romans, Crusaders & Saladin's Army, and French & English armies from the 100 Years War.