With the Sixth Coalition forming after French defeat in Russia, on 24 February 1813 Napoleon ordered the Petersburg Citadel to prepare for siege, visiting the city on 25 April to inspect the fortifications, in particular both Citadels. The French authorities banned all burials in city cemeteries from 26 June 1813, setting up a single central cemetery in , an arrangement that continued until 9 December 1816 after the city had been restored to Prussia. After the imposition of martial law on the Petersberg Citadel in 1813, the was used as a warehouse and the were reburied in Erfurt Cathedral.