The Bonn Silver Mines were a network of mines to the east of Prague, which supplied the city with silver during the time of the First Crusade. In 1141 A.D., Ahzra the Unliving invaded the mines with her army of szlachta, forcing out the miners and disrupting the commerce of the city. Using the mines as a haven and a base, she sent her szlachta on nightly raids into Prague, sowing terror among the populace. The mines were eventually recovered when a wounded Crusader named Christof Romuald descended into the mines and slew Ahzra.