The last major Roman civil war is thought to have been fought in the Vipava area in today's western Slovenia in 394. While written records of the Battle of the Frigidus exist, its exact location could not have been pinpointed so far for lack of material evidence. Yet the most recent archaeological finds could well change that.

The clash, also known as the Battle of the Frigid River, was fought in early September 394 between the armies of the Roman emperor Theodosius the Great and the rebel Eugenius. Theodosius' army would prevail and with it Christianity, with the bora wind that the area is known for believed to have contributed to its victory.

Researchers have so far thought the clash was located on a plain between Vrhpolje and Zemono Manor, where a local cultural association re-enacted the battle in 2009 and 2010. While no material traces have been found there, Roman weapons and other objects found a bit further to the north, in the Budanje area, could help unravel the puzzle.

Lead-weighted darts

Archaeologists from the National Museum of Slovenia have been exploring the site for a while, also using ground penetrating radar scanning and metal detectors. They are working on two sets of finds; the first were discovered by a local between 2016 and 2020 and handed over to a regional museum, while the others are those discovered by the archaeologists during fieldwork.

The National Museum told the Slovenian Press Agency the finds point to a military clash in the late Roman period, that is between 3rd and 5th centuries AD, when the Battle of the Frigidus (believed to be the Vipava River) took place.

Most of the finds are projectiles, iron arrowheads and spearheads that were are used by Roman armies in the late Roman period. "Some of them are twisted or damaged otherwise, such as when a projectile point hits a target," says Janka Istenič, a curator at the National Museum.

"The fact that they are damaged and the dispersion of the finds over a relatively wide area of around one square kilometre suggest that material traces of a late Roman military conflict have been preserved at Budanje," she says.

Many of the projectiles are plumbatae or lead-weighted darts, which were used mainly by infantry. "Such iron heads could pierce shields, and the barbs prevented them from being easily pulled out, for example from chain mail," head of the research, Vesna Tratnik, says.

The archaeologists believe they have discovered only a part of the battlefield. Written sources indicate that the battle was fought between Ajdovščina and the area rising to the Hrušica pass to the east. The village of Budanje lies between Ajdovščina and Vipava, near the Zemono Manor.

Finds not conclusive but significant

To confirm or refute the link between the objects found and the Battle of the Frigidius, further field research will be required, followed by an in-depth analysis of all the finds and data. Test excavations are underway at the site, which have so far been used to investigate part of the Roman building, the burial site and a scattering of Roman coins, says Tratnik.

They have excavated two cremation graves with several urns and an inhumation grave. In addition to the urns, the cremation graves also contained ceramic jars, pots and part of an amphora, as well as three iron knives. They have also found an iron combat knife, about 30 centimetres long, typical of the late Roman period.

Whether this is indeed the site of the famous Battle of the Frigid River could be clear within a few years, the museum says. The site has international significance, regardless of its connection to the battle, as there are no other sites with clear material traces of late Roman military life that would have been discovered at an original site.

"As a rule, most of the material remains were taken from the battlefields: first by the victors, who took the most valuable objects or parts of them, then by many others, including the local people. The removal of material traces of the fighting would continue, especially in areas of intense human activity," Istenič says.

Battle to be re-enacted again this year

The Battle of the Frigidus is considered the last major Roman civil war. Theodosius the Great, who declared Christianity the state religion in 380, defeated Eugenius, who wanted to re-establish paganism. According to Ancient Roman sources, Eugenius' soldiers switched sides en masse and Theodosius also benefited from gale-force winds that turned away the arrows fired by Eugenius' army.

Theodosius, the last emperor o rule the entire Roman Empire, died a year after the battle. His sons became emperors, one ruling the Western and the other Eastern part of the Empire.

Marking the 1600th anniversary of the battle, a monument to Theodosius was erected in Vrhpolje on the spot where he is believed to have prayed before the battle. This summer the battle will be re-enacted again in a spectacle that is expected to attract around 15,000 visitors. It will be held as part of the European Capital of Culture in Nova Gorica and Gorizia.