- Catholic Encyclopedia: Crusades
- An extensive history of the Crusades.
- Crusades
- A large and still growing section of very clear and attractive maps (and remakes), an in-depth chronological overview, a large segment on Crusader castles, an extensive bibliography – and much more about the Crusader area.
- Crusades
- The Online Reference Book for Medieval Studies’, an online encyclopedia, crusades page. Background essays and links to related sites.
- Fourth and Later Crusades Map
- Detailed map with routes, set in 1204 AD.
- Jerusalem during the Crusades
- A map of Jerusalem with locations of major churches and gates.
- Second and Third Crusades
- Map of the territories held during the second and third crusades, political boundries c. 1189.
