Crusades: The siege of Damascus ended in a decisive victory for the Muslims, leading to the disintegration of the Second Crusade. Siege of Damascus (1148): The siege of Damascus took place between 24 and 28 July 1148 O.S. during the Second Crusade. Two Crusader armies from Europe and the army of the Crusader Kingdom of Jerusalem attempted to lay siege to the Seljuk Empire city of Damascus. The effort ended in a Crusader defeat. The battle occurred as the alliance between the Kingdom of Jerusalem and Mu'in ad-Din Unur, emir of the city of Damascus, was unraveling and the Crusader County of Edessa was falling to Imad al-Din Zengi, emir of the Seljuk city of Aleppo. July 28, 1148. Wiki link