The DMMapp (Digitized Medieval Manuscripts App) links to more than 300 libraries in the world. Each one of these contains medieval manuscripts that can be browsed for free.
Tournament Joust is a free print and play game with some really good looking jousting mechanics. It has paper knights, but you’ll want to swap in your own miniatures.
The Internet Medieval Sourcebook is a fantastic resource for miniature wargamers. I’ve had this one in my bookmarks for several years and haven’t even begun to plumb its depths. The section on the Crusades is particularly useful.