 He successfully defended the Schlossberg against eight attacks, but they were forced to give up after the Grande Armée occupied Vienna and the Emperor ordered to surrender.Following the defeat of Austria by Napoleonic forces at the Battle of Wagram in 1809, the fortifications were demolished using explosives, as stipulated in the Peace of Schönbrunn of the same year.The belltower (Glockenturm) and the civic clock tower ("Uhrturm"), which is a leading tourist attraction and serves as a symbol for Graz, were spared after the citizens of Graz paid a ransom for their preservation.