Penguin Publishing
Penguin Random House: "The Door in the Wall" Teacher Guide
"The Door in the Wall" Teacher guide includes brief synopsis, author biographical sketch. list of themes, and ideas for interdisciplinary connections.
Other
Northern Fortress
A great description, history, maps, photos, and reviews of the northwestern fortresses of Finland and Russia. Many of these fortresses or castles date to the 12th and 13th centuries.
Massachusetts Institute of Technology
Mit: Open Course Ware: The Emergence of Europe 500 1300
Enhance your learning of European history with the materials provided in this online course. Include suggested readings, assignments, and exam questions.