 Complete the following phrase:  In 1810 the Tyrolean fighter Andreas Hofer was imprisoned in the castle before his execution by the Kingdom of Italy. Mantua became part of the Austrian Empire in 1814 and from 1815 it was a maximum security prison for the Empires political opponents, such as the Belfiore martyrs from 1852 onwards. Others pro-Risorgimento figures imprisoned there included Ciro Menotti and Teresa Arrivabene. The buildings structure was damaged by the 