On the ridge called Vrata (the “Gate”), archaeologists recently confirmed a new section of the claustra Alpium Iuliarum barrier system. On the basis of a lidar record, field research and archival documents, the modest remains of the once mighty barrier wall were documented in the area between Planina near Cerkno and Podpleče in the Cerkno Hills (Cerkljansko hribovje).
The barriers of the CAI system are evenly strung from Rijeka in Croatia towards the north to the most fortified part between Vrhnika and Ajdovščina. From here to the northernmost known barrier at Zarakovec in the Bača Ravine (Baška grapa), there was an empty area at the space of the Cerkno Hills. In the archive sources, a longer Roman wall is mentioned in this area, which guarded the passage from the Poljane Valley (Poljanska dolina) to Cerkno, on the ridge called Vrata (the “Gate”). The toponyms at the ridge (“Vrata” the (“Gate”), “Na vratih” (“At the Gate”) and “Za zidom” (“Beyond the Wall”)), which most likely indicate a passage, a pass, perhaps even a wall or the gate in the wall, are also significant.
On the southern part of the route, the wall in the length of 130 metres was completely destroyed already in the 1990s due to major agricultural interventions. The main 360 m of the route were also destroyed already during the time between the two wars. In the framework of the construction of the Alpine Wall, the Italian army set up a heavy armament there in order to consolidate the border between Italy and the Kingdom of Yugoslavia. The remains of the wall are very modest also on the northern part of the route, where we can follow them 250 metres. They can be observed on the forest ground as an earthen, about 1 metre wide embankment, from which stones protrude in some areas. The entire barrier was at least 740 metres long.
The Vrata barrier is located at the pass between the Poljane Valley and Cerkno, the strategic importance of which is also proven by numerous remains of military facilities from other periods. In the antiquity, there was a road in this area connecting the area of Škofja Loka with Posočje. Although the main connection with Italy led through Ljubljana (Emona) and Ajdovščina (Castra) to Aquileia, it was dangerous in the turbulent times of the Late Roman period and the traffic on it was reduced. The side routes became more important. One of them led through the Cerkno Hills, precisely across the Vrata pass, which is why the Romans established control there by means of a wall.