There was a fortress on the castle hill of Deva, even in ancient Roman times. The medieval castle was probably built after the Tartar invasion. The protective walls from three different ages climb up to the top of the mountain in a spiral line. It was first mentioned in a written source in 1264 as a royal fort. The Transylvanian voivodes administered it for a long time, and later it was owned by the Transylvanian princes. It was considered an impregnable fortress; that is why the Turks never tried to besiege it. In 1579, Ferenc David, founder and first bishop of the Unitarian Church in Transylvania, was imprisoned and died here. He was sentenced to imprisonment on the charge of Reformation/Neology under the reign of Kristóf Báthori. István Dobó, the hero defender of Eger against the Turks, was held here captive. The last fortification work on the fortress was carried out by the Military Council of Vienna between 1717 and 1719. After that, it gradually became out of date. Emperor Francis I. was the last ruler who commissioned repair works. In 1849, an exploding powder depot killed 100 soldiers and destroyed part of the castle, sealing the faith of the fortress. Its ruins are being restored today. The famous Hungarian folk ballad Clement Maison’s wife is linked to the history of the fortress of Deva.