AB One Games have released a new historical rule set called Bad War.
From their website:
Bad War is the fourth set of wargame rules using the AB One system. Previous titles include Father Tilly which covers the Thirty Years War and Bloody Kingdom, a set of English Civil War rules. Bad War is designed to cover warfare in the sixteenth century, a period which seems from this distance to offer the wargamer a terrifically interesting and colourful selection of gaming opportunities. Full of garishly dressed soldiers, colourful and exotic troop types and with the introduction of the firearm, the beginnings of modern warfare. Armies struggled to find a way of incorporating this new technology, much time was devoted to experimentation with battlefield tactics and still the tried and tested methods of medieval warfare produced dramatic victories. Few could stand against the awesome charge of the French Gendarmes nor face the ferocious onslaught of the Swiss pike-square. And yet warfare did evolve during this period. The arquebus and musket do replace the bow and crossbow, knights begin to put aside their lances and take up the pistol.
What I have attempted with Bad War is to bring out the qualities of some of these more exotic troops, the Doppelsöldner, the Aventuriers, the Black Bands, the Gendarmes, the Landsknechts, the Stradiots and the Condottieri. Rather than a simple factor rating their quality, these troops have different characteristics that shape and modify their actions. Gendarmes are likely to disobey orders and attack their nearest opponents, the Swiss will seek out any Landsknechts and visit bloody slaughter on their foe and any Stradiots can certainly be relied upon to loot the baggage train – either their opponents or their own!