The Alba Iulia citadel, designed by Italian architect Giovanni Morando Visconti, was built between 1716 and 1735, using the Vauban military architectural system—the largest of this kind in Southeastern Europe. The fortress is outstanding both for its architectural elements and for the beauty of its six gates, unique in European military structures. Doubtless the artists, sculptors Johann Koning, Johan Vischer and Giuseppe Tencalla, had been inspired by ancient mythology.

About 7.2 miles of ramparts made of brick and quarry stones form a seven-point star shape with seven bastions (Eugene of Savoia, St. Stefan, The Trinity, St. Michael, St. Carol, St. Capistrano and St. Elisabeth) guarded by six monumental gates.

The gates, valuable samples of early baroque style, have served as a model for 18th century Transylvanian architecture.

The City of Alba Iulia is one of the few localities in Romania that have been fated to gain an important position in the history of human settlings and fortifications, from pre-history to modern ages. The bulwark fortress of Alba Iulia has been set up between 1714 and 1738 and it is considered to be the most representative of Vauban type in Romania. The fortress was designed by the Italian architect Giovanni Morando Visconti.

The Italian architect Giovanni Morando Visconti has made the project of the fortress. He was guided by the general Stefan de Steinville and later by general Weiss. The work at the fortification of Alba Iulia has began on the 4th of November 1715, when the foundation of Carol bulwark, dedicated to the emperor and situated on the Northern side was made. Weiss named his project, the fortification, "Alba Iulia's major fortress in the Principality of Transylvania".

Between the 18th and 19th centuries the fortress has served as the military center of Transylvania and also as general armament dump. The perimeter of the walls is about 12 km; 20.000 serves built the walls.

The fortress has seven bulwarks (Eugene of Savoia, St. Stefan, The Trinity, St. Michael, St. Carol, St. Capistrano and St. Elisabeth) that make it a star shaped one, common to Vauban fortresses. The biggest bulwark is the Trinity one, measuring 116 and 135 m and being decorated in the center with a blazon crowned by outlines and acanthus leaves.

The walls were made of bricks, quarry stones, or out of the Roman ruins, measuring 3 m at the base and 1.20 m at the top, being sustained by abutments in order to neutralize the earth's force. The six gates of the bulwark fortress have been a model for the 18th century Transylvanian architecture. They are looked upon as extremely valuable samples of early baroque.

The planning and the building of the fortress led to the modification of the street texture; that is why the six gates had been placed three towards the town and the other three towards the western drill field. All the roads and the fitted gates were functional. The fortress is outstanding both for its decorative elements and for the beauty of its six gates, unique in European military architecture. Doubtless the artists had been inspired by ancient mythology. Sculptors like Johann Koning, Johan Vischer and Giuseppe Tencalla had made the decorations. On the whole, the fortress stands out as the most important baroque figurative plastic pile.

The six gates of the bulwark fortress have been a model for the 18th century Transylvanian architecture.  They are looked upon as extremely valuable samples of early baroque. Sculptors like Johann Koning, Johan Vischer and Giuseppe Tencalla had made the decorations. On the whole, the fortress stands out as the most important baroque figurative plastic pile. Today, only three gates preserve the original look.

The First Gate.
It is situated at the base of the fortress and has been built out of stones carved like a three gates triumphal arch. The gate has the Austrian blazon ( the two headed eagle, the sward and the scepter) in the middle, between the statues of the god Mars and the statues of the goddess Venus. The inside is carved with antique mythology bas-relief, representing legendary hero Hercules fighting Nemeea lion and Perseus holding Medusa’s cut head.

The Third Gate and Horia's Cell
After the second gate, out of which only the lateral pylons are preserved, next follows the most important and most grandiose of the gates, the third gate. It actually represents the entrance to the fortress. It is situated on the curtain, half way between the St. Eugene bulwark and St. Capistrano one.4 pillars and 8 pilasters hold the archway and the vault of the three gates. Richly adorned, it is considered representative for Transylvanian baroque sculpture. The front stands out for the Carol the sixth’s equestrian statue. Two ottoman prisoners, terrified under the hoofs of the victorious emperor’s horse, are sculptured on the pedestals of the statue. The Austrian blazon with the two-headed eagle, with Transylvanian blazon on its chest is carved on cornice. The bas-relief on the left side represents the allegory of the glorious general receiving Alba Iulia`s scale model after his brave victory over the ottomans. Inside the pedestal of Carol’s statue there is a small room that, in 1785, January 2, had served as cell for Horea the main leader of the great serves revolt from 1784-1785. In 1937, a stone plaque with the carving: "This where he had suffered with bravery, determination and trusting the future of Romanian people 27th of December 1784 - 28 of February 1785". On the side there are four statues, symbolizing the great virtues temperance, wisdom, welfare and force.

The Fourth Gate
The Fourth Gate, also in baroque style is situated next to the two cathedrals. It is one of the entrances to the Roman Plateau. The building is the common one, and was probably used as shelter for the guards; it also contains a semi cylindrical vault on two Atlantis, resembling the one at the Third Gate; the elementary Austrian blazon; bas-reliefs of trophies, canons and Carol the sixth’s flags.

The Citadel is easily accessible for tourists. The best way to get to Alba is by airplane to Bucharest, and then – by car to the town.