This rule set is derived from Warmaster - some might even say it's an improvement on Warmaster! It certainly provides for great games.
We play it using figures in various scales, 6mm and 10mm (on standard sized bases) and 15mm using larger bases, 60x30mm.
We're also developing variants (as so many have done).
Currently in use are English Civil Warmaster and Renaissance Warmaster (for the 16th century, including the Italian Wars). Both are works in progress but give good games already. Eventually these two variants may well end up being combined and extended to provide a single renaissance variant, covering 1495-1700. Maybe.... we'll see! They are both to be found on the Renaissance Warmaster page.
Colonial Warmaster - coming soon!
There is an official discussion group for Warmaster Ancients that's worth a look, as well as an unoffical mailing list which covers all historical variants.