The fortress was built on the right bank of the river Someşul Mic at a distance of only a few kilometers from the ruins of the Roman camp Secunda Pannoniorum and around the small village of Gherla small village, now a city. Led by architect Domenico da Bologna (1540-1551), the fortress was built as a quadrilateral with bastions at the corners, surrounded by 3 to 4 meters thick walls and a moat, with a mobile bridge (on east side), and there is access through a series of underground tunnels. As building materials were mainly used the remains of Unguraş citadel. Over time the fortress became possession of several noble families, including the princes of Transylvania - Sigismund Bathory (1580) and George Rákóczi II (1648), making it a princely residence.
Postcard from here
In the early 17th century the fortress lost its strategic importance, so in 1706 it was originally transformed into barracks, was then abandoned and put up for sale. On October 20, 1785 Emperor Joseph II transformed the citadel into a central jail in Transylvania (Carcer Magni Principatus Transilvaniae). The transformation followed to a mass escape from the Trei Scaune county prison, so the noblemen desired to create a maximum security prison in Transylvania. Between 1857-1860 was built the central pavilion as a special detention place by the architects Danil and Ioan Reschler from Bistriţa; here was also the 6-rooms apartment of the director.
Photo from Gherla News
On May 1, 1913 the prison is converted into a prevention institute for minors, where children studied and learned trades. During the Communist regime it became a political prison (1945-1964), and a common-law prison (1964-1989). The Gherla Prison, one of the oldest in Romania, became a maximum security prison since 1989.