Urban II's big claim to fame is that he authorized the First Crusade, a call for European Christians to take back the Holy Land from the Seljuk Turks.* At the time, the Seljuk Empire was apparently making a lot of trouble for the Eastern church, based in Byzantium. Wikipedia asserts that one of his speeches cajoling the West was the
SINGLE MOST EFFECTIVE SPEECH IN EUROPEAN HISTORY, which sounds like there should be statues and gold medals involved. Here's his big quote:
I, or rather the Lord, beseech you as Christ's heralds to publish this everywhere and to persuade all people of whatever rank, foot-soldiers and knights, poor and rich, to carry aid promptly to those Christians and to destroy that vile race from the lands of our friends. I say this to those who are present, it meant also for those who are absent. Moreover, Christ commands it.
Not bad, huh? It worked, too - Urban II oversaw most of the First Crusade, dying just after Jerusalem had been captured in 1099. (That's another 12-year reign, for those of you keeping score).
*By the way, can anybody recommend a good book about the Seljuk Empire? I've been looking for histories about the Middle East from say, 500-1500AD**, but can't seem anything that looks promising.
**I know, I know! I'm such a dork.