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  • Writer's pictureStefan Ivanov

Late Antique Fortress "Sthenos"

Updated: Feb 20, 2023

Stenos fortress in Trajan's Gate pass, called by Romans and Thracians Succi (in Latin Succi), was part of a huge fortification system, including an ancient fortress wall with a massive and majestic triumphal arch (gate) Trajan's Gate and several fortifications, located on Mount Eledzhik and Dolna Vasilitsa.



After the archaeological excavations, a massive building, probably a military garrison, was revealed, with a wide courtyard, three defensive towers and six entrances.

The construction technology, as well as the coins found, indicate the period of its construction (the end of the fourth century), which coincides with the reign of Emperor Theodosius (378 ÷ 395).


Stenos fortress, Trajan's Gate passage

The fortress resembles an irregular rectangle measuring 90 meters by 36 meters. It was built on a rock massif without being dug into the ground.

At the time, the Romans built defensive facilities in the passage from several fortifications, which played a deterrent role against any enemy invading the borders of the empire or moving along the Via Diagonalis - once the main road connecting Western Europe via Belgrade to Constantinople.

Ammianus Marcellinus (who lived in the fourth century) wrote that more than once the closure of access through this gorge was quite sufficient to repel the advance of great generals and even entire nations.

"Stenos" is located on one of the heights in the pass and covers an area of 350 square meters. In this way, the defenders of the area had an excellent view of the entire surrounding area.


Stenos fortress, Trajan's Gate passage

The main entrance of the fortress was from the north, flanked by two pointed pentagonal towers, which provided significant advantages to the defenders. The two towers are said to be unique in appearance for the territory of the Balkan Peninsula.

The remaining entrances (called poterni) are small gates, used mostly for defense of the garrison. Strategically, they are excellently placed in places around the eastern and western ramparts and one on each of the three towers.


Stenos fortress, Trajan's Gate passage

On its southern side, the impressive antiquity was guarded by a huge tower with a triangular shape.

The fortress wall was built using the Roman construction technique opus mixtum, in which stone blocks and a brick belt alternate. The thickness of the wall is two meters and twenty centimeters.

The estimated height of the wall, including the buttress, is twelve meters to the north and fifteen meters to the south.


Stenos fortress, Trajan's Gate passage

In the courtyard of the fortress, dug into the ground, you can still see clay vessels that once served to store food and grain. Of essential importance was the time the defenders would last under siege. Sufficient food supplies, as well as a solid and uninterrupted source of fresh drinking water, were therefore a must. Under the western wall of the fortress, an underground vaulted tunnel, about sixty meters long, was discovered, which led to an underground spring.

Fortifications in the pass included three fortresses and a monumental arch that was built on the road itself, at the highest point of the pass.

The arch was connected to two of the fortresses by means of defensive walls, thus blocking the entire gorge and making passage impossible.


Stenos fortress, Trajan's Gate passage
Marsili's sketch

The huge arch of the Roman gate was eighteen meters high!


It was called Trajan's Gate and somehow miraculously it was preserved until the nineteenth century.

It is said that through this massive gate it was possible for a horseman to pass with his pike raised. On both sides of it rose high stone walls that blocked the passage.

This monumental gate struck everyone with its size, unusualness and grandeur.


Every traveler or stranger who passed by here was so impressed that he told and wrote about her.


The Italian Luigi Ferdinando Marsili (1658 – 1730), a prominent specialist in military affairs and an excellent diplomat, enchanted by what he saw, thoroughly studied the arch.

A preserved sketch of him has survived to this day.

Thanks to his work, today it is clear what Trajan's Gate looked like.

Marsili describes it as a giant arch, 15 feet wide and 24 feet high.

Visiting it, he found the central arch literally overgrown with greenery and sketched it just like that.

I can find a copy of Luigi's sketch today in the information center at the fortress.

I'm filming it for you.

I continue to listen to the informational guide with great interest and soak it all in!

Today, archaeologists and historians continue to argue on the subject - is the gate the work of Emperor Trajan or is it more of a Byzantine construction, with the arch getting its name as an analogy to Trajan's passage.


Who knows?


The fact that today the location of the arch is known with precision is extremely interesting. What's more, its foundations have been discovered and funds are currently being collected for its complete restoration according to Marsili's sketch.


Evidence has been collected that the surrounding area was also used in the Middle Ages (in the ninth-tenth century), which makes it an important Bulgarian stronghold.

Three of the Crusades passed through here.

In the Middle Ages, the passage was called the King's Gate (in Greek, Василики полти).

After the invasion of the Ottomans on the Bulgarian lands, the functions of Trajan's Gate as a guardian of the pass were lost. Unused and unmaintained, the hardwood begins to crumble. However, the pass has always had important strategic importance and has played a major role throughout the centuries.


To this day, the passage continues to serve people.


How do you get here?

Pass Trajanovi vrata, is a saddle connecting the Ikhtiman valley with the Upper Thracian lowland.



The fortress is located by the highway Trakia, about 17 kilometers from the city of Ihtiman, about 15 kilometers from the city of Kostenets, about 60 kilometers from the capital and about 72 kilometers from the city of Plovdiv.

If you are traveling on the highway, stop at the village of Mirovo, heading along the old Tsarigradski road.

The road winds along the southern slopes of the Eledzhik mountain range and offers a wonderful view of the mountain peaks of Sštinska Sredna Gora, Rila and Rhodopes.


The currently restored Stenos fortress was officially opened for visits on August 16, 2015.

The fort is open for visits every day from 9:00 AM to 6:00 PM.

In front of the information center there is a wide and shaded parking lot where you can leave your car.

A nominal entrance fee is required.

Allow between 30 and 60 minutes to explore it, if you will also be taking photos.


Before I wish you a “Pleasant Visit!” I would like to be sure that as you walk through more of the impressive antiquity, you will be well informed of what great events it has witnessed.


I also express my sincere thanks to the information guide who met me late on Sunday and after the end of his working day, although he was visibly tired, he was kind enough to tell me all that I am sharing with you today.


Thank you!


Access to the fortress today is possible for all persons of all ages!

Wheelchair access is also provided!


I wish you an exceptional and impressive walk!


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