Fortress Castra


Fort with Tower behind Lavričev square
Fort with Tower behind Lavričev square

Roman fort Castra with 14 towers was built around year 270 and was involved in the defense system of the eastern borders of Roman empire – Klaustra. Today is, among all Slovenian places, only in Ajdovščina preserved almost completely condensed Roman period walls. Ajdovščina developed for centuries exclusively indside the walls. Old Roman fort, even centuries after the disappearance of the Roman empire, with its walls and towers still today forms the living of Castrians. Walking in the streets, where the modern sealing is impressively interwined with the old walls of Castra, reminds us that history never wanes. It is because of the architectural combines of old city town with wall of Roman military fort, Castra gotten flattering name of “Slovenian Diocletian’s Palace”.

Legend says that Slavs, when they spotted the mighty ruins of Castra, attributed its construction to the giants with a human face, Ajd. From here Ajdovščina got its name.

The history of the settlements of this area dates back in the Bronze and Iron age, when the fortified settlement stood on the hill Gradišče (Školj), which lies north of Castra, in confluence of Lokavšček and Hubelj. In year 181 BC the Romans founded Oglej (Aquileia), administrative, military, commercial and cultural center that served as a springhold for conquering of the southeastern Alps and Danube region. They built the road through Vipava valley, which led under Školj in direction Razdrto (Ocra) and further towards Emona. At the site of today’s Ajdovščina was in early imperial era, if not earlier, built mail and freight station with name Fluvio Frigido (at the Cold river – Hubelj), the last lowland station before the road began to climb. After the conquest of the Alps and Danube in the early 1st century AD, Romans built newer and shorter road to Emona, which led over Col, Hrušica, Logatec and Vrhnika. Ajdovščina was mentioned in three itineraries: Tabula Peutingeriani from beginning of 3rd century as Fl. Frigido, in Antonin’s from end of 3rd century as Fluvio Frigido and in Jerusalem from first half of 4th century as mutatio Castra.

Castra tower infront of First Slovenian government square
Castra tower infront of First Slovenian government square

The political situation in Roman country in second half of 3rd century and in the beginning of 4th triggered the decision to construct the fortifications and system of prison walls between Kvarner and Čedad, named Claustra Alpium luliarum. North of Mansia they built nwe fortress – Castra, which besides the civilian tasks takes over also military tasks, becomes operational military center with a permanent military command and crew. Presumably Castra is depicted in the inventory of palace, administrative and military titles Notitia dignitatum from 5th century. In antique written sources is Ajdovščina associated with two military conflicts. First was the battle between the usurper Eugenius and the emperor Theodosius in year 394 at Cold river in Frigid. Today it is generally accepted that the battle took place on the plain between Ajdovščina and Vipava. Eugeinus went to the battle from Castra, Theodosius from Hrušica. From world history event inspired Roman poet Claudianus, attributed Theodosius victory to violent Ajdvoščina bora, which shifted the arrows and broke the power of the opponent.

In second battle, the Lombards defended the eastern border from the advancing Avars and Slavs. Armies fought at Flovius. Life in the ruins of Castra dies at the end of 6th century or at the beginning of 7th.


The fort has a floor plan in shape of an irregular polygon. The lenght is 220 meters, wide is 160 meters, the total volume is around 600 meters. In 3.4 meters thich walls are included 14 round towers. Towers, which have square bases, were at leat 6 meters high. The outer diameter of the towers is 9 to 9.6 meters and inner less than 3 meters. The distances between the towers are different, from 28 to 55 meters, usually between 30 to 34 meters. Around the walls is 3 meters wide trench. The entrance was on the west side, between towers 1 and 3. The interior of the fort was due to subsequent alterations, demolitions and newer sealings poorly known. Archaelogically investigated ware two locations, on the spot of Bratina house and under the store Nanos. They found the remains of several buildings, spas and sewer. The Forum was probably on the sit of today’s main city square. The cementery, which streches to the west of the walls, is mostly destroyed. Known are only 22 urn or skeletal graves.


While visiting Ajdovščina, take time and go to an unforgettable walk into the distant past of the city. Circular path is, in different directions around the walls and through the small markets, connected with the central city square, the former fort Forum.


travel-slovenia-link-on-othertravel-slovenia-link-on-other2See other Roman Empire sights in Slovenia!


travel-slovenia-floor-plan-of-castra-viewFloor plan of Castra
Floor plan of the fortress Castra with walls and cemetery. Dashed lines are showing the other parts, where the walls used to be. The fort has a floor plan in shape of an irregular polygon. To view the map in full size, just click on the image on the left or on the link to open it in another window. [_See the map_]

Ajdovščina is a city in the central part of Vipava valley, at the confluence of the stream Hubelj and Lokavšček, on the contact of Ajdovščina field and flysch slope below Gora (Sinji peak, 1002 meters). The city lies along the main road, which through Ljubljana connects central Europe with northern Italy. [_Read more_]

travel-slovenia-valvasor-battle-between-theodosius-and-eugene-viewThe great battle
On 17th January 365 in Milano died Roman emperor Theodosius 1, with full name Flavius Theodosius, named also Magnus (the Great), who on 5th and 6th September 394 at the battle in Frigid defeated anti-emperor Eugenius and victoriusly ended the long-term civil war. [_Read more_]