The title of this post is a bit misleading. The Council of Clermont actually ran from November 18 through November 28, 1095, so November 27 commemorates neither its beginning nor its end. What it does commemorate, however, is the day on which Pope Urban II (d. 1099) got to the point. It was on November 27, the second to last day of the council, when Urban turned its focus onto the challenges facing the Byzantine Empire in the east in the aftermath of the Battle of Manzikert. Urban’s speech, calling for an army of Christian warriors to head east and drive the Turks out of Byzantine territory, kicked off the Crusades.
The bulk of the council was actually taken up with internal Church matters, like instituting the Benedictine Reforms of monastic life and a decision to extend the excommunication of King Philip I of France for marrying (well, kind of) Bertrade de Montfort, despite the fact that both Philip and Bertrade were, uh, already married to other people at the time. That’s a little awkward.
In fact, part of Urban’s rationale in calling for a crusade to the east, aside from a desire to rescue his fellow Christians (schismatic, but still) from the Muslim menace (and thereby maybe bring the eastern Church into his fold), was the fact that the political/religious situation in Western Europe was pretty tense. Philip obviously didn’t care for Urban, but that actually wasn’t Urban’s biggest problem. He’d inherited the Investiture Controversy, his predecessor Gregory VII’s feud with the Holy Roman Emperor, Henry IV, over whether the Pope or the Emperor had the right to appoint bishops and abbots in imperial territory. If you’re a good Catholic, then you probably know the story of Henry IV donning a hairshirt and walking barefoot over the Alps to Gregory’s palace at Canossa, where he knelt in the snow for three days waiting for an audience with the pope in order to beg forgiveness for his transgressions. That was in 1077. By 1080, a much stronger Henry appointed his own “pope,” who took the name “Clement III” and served as what’s (affectionately, I’m sure) known as an “antipope” until his death in 1100.
So Urban had a lot on his own plate, and he undoubtedly thought that this Crusade idea would unite Europe behind his leadership. That didn’t quite work out for him. Philip did finally agree at least to stop acting like he was married to Bertrade in 1104, but of course Urban was too dead by then to appreciate it. The Investiture Controversy similarly resolved itself after Urban’s death, when Emperor Henry V and Pope Calixtus II agreed on the Concordat of Worms in 1122. But that whole Crusade thing kind of took on a life of its own, didn’t it? The main Crusading movement, in and around the “Holy Land,” went on until 1291, and people were still using the term “Crusade” to describe Christian military campaigns against Muslim powers (and against Christian heretics) through the 15th century (or to the present day, if we go by some of the rowdier right-wing fever swamps).
Urban’s speech calling for the Crusade has been preserved in several forms, none of which entirely agree with each other. The biggest variation among them is probably the issue of Jerusalem. Pope Gregory VII had already issued a call for Christian lords to send forces to aid the Byzantines, but he’d been ignored. Urban recast Gregory’s purely military mission in religious terms, as a martial pilgrimage. Europe was full of Christians who spent their time fighting other Christians, which was immoral and even illegal under Church law. Urban gave these men a new enemy, and a war that wasn’t only legal but was practically a religious obligation. This was how he ensured that his call would get the attention that Gregory’s didn’t.
But did Urban call for the conquest of Jerusalem? This is where all the various accounts disagree–in at least one of them, Jerusalem isn’t even mentioned, while in others Urban makes taking Jerusalem the most important goal of the campaign. Obviously any chronicler writing after the First Crusade, which abandoned the Byzantines and focused on capturing Jerusalem, would have some incentive to write Jerusalem in to Urban’s speech in order to justify what actually happened. Reality may be somewhere in the middle. Urban himself talked about the coming campaign in a letter he wrote not long after the council ended, and he writes about the need to liberate the Christian Churches of the east without saying anything explicit about capturing the Holy Land. But the phrase “the Christian Churches of the east” presumably includes, presumably especially includes, churches in Jerusalem, so I think at least you have to say that Urban wasn’t uninterested in having his Crusaders try to capture the Holy City.