Medieval Religion
Huge list of annotated links, including famous works like St. Augustine's City of God

List of Popes
Completing listing of all of the heads of the Catholic Church, from the beginning to the present day

The Crusades
The Crusades were a series of military expeditions by Western powers to "retake" the Holy Land from the Islamic powers that had "taken" it.

Papal Encyclicals Online
Selected listings all the way back to 1216

Catholic Church History
Huge listings of events and links, for all time periods

Medieval Religion: Theology and Philosophy in the Middle Ages
Collection of links to various relevant writings

Bernard of Cluny
So-called originator of the influential Cluniac order

Pope Gregory VII
Pope during the 11th Century who is best known for his epic struggle with Emperor Henry IV

Gregory VII's Dictatus Papae
Dictates of the Pope issued in 1090

Pope Urban II
The religious leader who began the Crusades Urban II desperately wanted to reclaim the Holy Land and encouraged many of Europe's most powerful leaders to join in the quest.

Pope Urban II: Speech at the Council of Clermont
Read the words that stirred so many kings and knights to march to Jerusalem.

The Church and the Jews in the Middle Ages
Focus on persecution of Jews by Christians in medieval times

The Inquisition
One of the most horrific features of the Middle Ages

The Summa Theologica
Massive work written by Thomas Aquinas