In 1782 it was converted into a prison, and in the following decades many renowned revolutionaries suffered there. Among others, the leader of the Greek independence struggle Alexander Ypsilantis from 1821 to 1823, Ferenc Kazinczy, a Hungarian writer and language innovator, and 42 participants in the Martinovics conspiracy. A prisoner, Russian revolutionary Mikhail Bakunin and Ferenc Rendl Guard Captain, who in 1832 committed an assassination against King Ferdinand I of Austria. The prisoners were kept in chains in extremely bad conditions.