I mentioned recently that in the 1980s we enjoyed playing Renaissance games with a set published by Dodo. I am glad to report that they are available as a free download from Wargame Developments, at the following link.
The author was John Armatys.. These were billed at the time as a Big Battles rules set, being much less detailed than the then-prevalent fashion for complicated calculations and record keeping. In many respects they would fit in well with today's rules The movement, shooting and combat systems are simple and easily remembered. The morale system is especially elegant: units accrue counters that slow down movement, impair fighting ability and make reaction tests harder to pass. Stationary unengaged units can remove counters, while each morale class can only take so many counters before being broken. It is important to try to take stressed units out of the line as they can be ground down pretty quickly in the presence of the enemy.
The one thing I miss in these rules is a command system: generals are only really used to rally units. I imagine today's tastes would prefer to see more limitations on a player's freedom to move his units. But I'm sure this could be remedied with a 'patch' from another rules set.
I would recommend these rules to more than just fans of Old School wargames. They give a fun game that is actually quite close to today's streamlined style. We will be using them for our next Renaissance game.