When it comes to RPGs emulating an authentic Medieval experience there are generally only two games that people go to; Pendragon and Chivalry & Sorcery. One could argue how authentic each of these are, but in general, they are far closer than D&D or anything else on the market.
Chivalry & Sorcery has been around nearly as long as D&D (1977 and 1974 respectively) and like many gamers my age we saw a lot of ads for it in the pages of Dragon Magazine, especially the Fantasy Games Unlimited 2nd Edition.
Currently, it is in its 5th Edition and is published by Brittannia Game Designs.
I am not going to review it today, but this is a gorgeous book. It is also a huge book at 600 pages.
I picked mine up from my FLGS a while back for some ideas on various campaigns, but now I am going to try it out on its own instead.
Brittannia Game Designs recently released the 5th Edition in a Print on Demand format AND a brand new "Basic Game."
The Basic Game is just about 80 pages and will cost you a whole $2.00. So well worth it for any D&D refugee.
I recently got my wife into the Showtime series "The Tudors," so maybe I could use that as an "in" for this game.