In the period June 22 – July 16, 1479, Stephen the Great built or rebuilt the stone fortress of Kilia. The Levantine or Greek-Genoese architect Ioan Privana, who built the Moldavian church of St. Nicholas here, could be involved in the construction works. After 1484 the stone fortress of Kilia was repaired and modernized by the Ottomans. At that time, each major province of the Ottoman Empire had its own chief architect of the Royal Corps of Architects, who dealt with military projects. It was a time when Ottoman specialists created engineering works that even met the standards of the following centuries. In the 18th century, the architect from the city of Hassa Halife Abdullah, the bina emini El Hac Hasan, the kapıcıbaşı Hasan Aga, the nazir’s deputy Salih Efendi, the Ottoman Empire architect chief Mehmed Tahir Aga, El Hac Ahmed, El Hac Emin and others were in charge of the fortress of Kilia in the Moldavian Principality. The stone fortress of Kilia functioned until 1795, when it was demolished and replaced by a bastion fortress of the Vauban type, built by the French engineer François Kauffer at the behest of Sultan Selim III.