Hello!
The siege of Damascus started in July 16, 1148 and ended on July 21, 1148.
This whole thing started is because King Louis The 7th of France wanted to take back Edessa from the Muslims. Louis abandoned the campaign and looked south of Edessa towards Damascus. this was because it was much closer. fun fact Louis chose a place to attack in an apple orchard because there was food to food his army. When the Muslims noticed they were losing they called upon another group of Muslims who were led by Nur Al-Din. King Louis then moved his army to the other side of the city, There was no apple orchard but the walls were a lot weaker. When Nur Al-din showed up, the crusaders then decided to retreat back home. so in the end this was a failed attempt at such a massive city.
Hope it helps!