The Rector's Palace (Knežev Dvor; after 1435) was built by Onofrio di Giordano della Cava (fl 1438-1455) in a Neapolitan Gothic style. After a gunpowder explosion in 1463, Michelozzo's new design for the first floor remained unexecuted, but the portico was rebuilt (1468) in the Renaissance style by the Florentine architect Salvi di Michiele and local masters. The combination of Renaissance arcades and Gothic windows in the piano nobile became so fashionable that it was adopted for other residences, including the Sponza Palace. In addition to the Rector's Office and his private chambers, the reception and audience halls, the Rector's palace was the seat of the minor council and of the state administration (Secretary, the Notariate and the Cadastre), the armory, the powder magazine, the watch-house and the prison.