The Second Crusade consisted mainly of a huge expeditionary force led by the French King Louis VII and the German King Conrad III. Its story is one of great initial promise and high theater, ending in disappointment and disaster. It was also was the first time that reigning monarchs went on Crusade.
Pope Eugene III came to Paris, where Louis staged a dramatic Mass at the Cathedral of St. Denis. Louis prostrated himself on the floor before the Saint, committing himself to holy war, then immediately set out. Louis was not really a warrior; he had been the second son, devoted to the church. In his short reign, he had already been forced to lead knights against rebels, but he came away from that experience with a deep sense of guilt. (Not all imaginary: he had burnt down a church with a thousand people sheltered inside.) His chief purpose was pilgrimage, and his appointed regent was the Abbot who had mentored him, rather than a nobleman or relative. Normally, the regent would be the Queen, but in this case, his wife chose to come along on the adventure.
The German army set out first, with a time lag to allow the countryside to recover from provisioning them before the French army passed through. In this way, both came to Constantinople and set out across Anatolia. Emperor Manuel was on bad terms with the Germans, good terms with the French. Cooperation wasn’t very good. In any case, both the German and French armies were decimated by Turkish attacks as they crossed the plateau. In one assault, King Louis had to climb a rock or cliff, holding onto tree roots while using his sword as rear guard. Both kings arrived in Antioch alive, but their armies were very badly reduced.
The obvious next step was to proceed to Edessa, since its capture by Turks was the casus belli. But they didn’t. King Louis wanted to see Jerusalem first, and there, the high council met and chose to attack…Damascus. This was foolish in both political and military terms. It was a miserable failure, as well. The allied forces of Zengi’s son Nur ad-Din and the ruler of Damascus pushed back the remnants of the Crusader forces. Had they attacked Edessa, Damascus probably would have sat out the fight. And that’s the crucial point: this was the first time Europeans faced a united Turkish force. They underestimated how much difference it would make.
The Crusader lords criticized how the European kings had bungled the siege, while the Europeans said the Crusaders had given up too quickly. When King Conrad went down to Ascalon to have a try at that old target, the other kings did not join him. Bitter, Conrad set out for home, leaving many captured noblemen to be ransomed by their families as possible. King Louis and Queen Eleanor went home in separate ships and soon after, they divorced (via an annulment of the “oops I guess we were cousins” kind). Bernard of Clairvaux felt terrible about having encouraged this mess in the first place; among his writings is a formal apology to the Pope.
Edessa never recovered; Nur ad-Din massacred the Christian population of the city, leaving it largely empty. It dwindled in economic importance and eventually became a ruin.