The Medieval Handbook

From the publisher website:

The Medieval Handbook:
A Sourcebook of 13th Century Europe

Wisdom, too, is Mightier than the Sword

This is a sourcebook on Europe of the 13th century, the inspiration for fantasy literature and roleplaying games. This book is written in the hand of a monk, Peter of Aalen, offering his perspective on the society and culture of the Middle Ages. This information is invaluable to your fantasy world, no matter what game you play, for it infuses brilliant color and rich texture into your tales. Particularly valuable to players of Ars Magica, this book presents the Hermetic perspective on Mythic Europe's society and culture.