The Siege of Jerusalem took place from June 7 to July 15, 1099 during the First Crusade. The climax of the First Crusade, the successful siege saw the Crusaders seize the city from the Fatimid Caliphate and laid the foundations for the Kingdom of Jerusalem.
Fig. 135 Rock Crystal ewer made for the Fatimid caliph al-Aziz. 975-976. Rock Crystal. One of the few surviving Fatimid court objects, carved from a single piece of rock crystal. al-Aziz ruled Egypt from 975 to 996. The crystal was imported from Afria and was velieved to prevent nightmares. Many of these precious artifacts were later melted down and sold for their metals. Treasury of St. Mark's, Venice. pg 253.