In 1599, a major reconstruction of the Cittadella begun, under designs of the military engineer Giovanni Rinaldini and under the direction of Vittorio Cassar. The southern walls of the city were completely rebuilt as a bastioned enceinte with a single bastion and two demi-bastions linked by curtain walls, along with two cavaliers, a ditch and outworks. Parts of the northern walls were also rebuilt by the Hospitallers, although they retained a medieval form. The walls surrounding the suburb Rabat were probably demolished at this point. The reconstruction to Rinaldini's and Cassar's designs was completed in around 1622.