(

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

for 'Barrier of the Julian Alps'; hereby, the term Julian Alps refers to the wider mountainous and hilly region from the

Julian Alps The Julian Alps (, , , , ) are a mountain range of the Southern Limestone Alps that stretches from northeastern Italy to Slovenia, where they rise to 2,864 m at Mount Triglav, the highest peak in Slovenia. A large part of the Julian Alps is inclu ...

to the Kvarner Gulf) was a defense system within the

Roman Empire The Roman Empire ruled the Mediterranean and much of Europe, Western Asia and North Africa. The Roman people, Romans conquered most of this during the Roman Republic, Republic, and it was ruled by emperors following Octavian's assumption of ...

between

Italia Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...

and

Pannonia Pannonia (, ) was a Roman province, province of the Roman Empire bounded on the north and east by the Danube, on the west by Noricum and upper Roman Italy, Italy, and on the southward by Dalmatia (Roman province), Dalmatia and upper Moesia. It ...

that protected Italy from possible invasions from the East. It secured the Postojna Gate, the land link between the eastern and western part of the empire, and thus the Claustra represented an inner border defense of the empire. Unlike a linear rampart, the Claustra consisted of a series of interconnected fortifications with its center at Castra ad Fluvium Frigidum (in the area of today's town of

Ajdovščina Ajdovščina (; ,trilingual name "Haidenschaft, Aidussina, Ajdovščina" inGemeindelexikon, der im Reichsrate Vertretenen Königreiche und Länder. Bearbeit auf Grund der Ergebnisse der Volkszählung vom 31. Dezember 1900. Herausgegeben von der K. ...

, the Vipava Valley); other important fortresses were '' Ad Pirum'' on today's Hrušica Plateau and '' Tarsatica'', now a part of the city of

Rijeka Rijeka (; Fiume ( �fjuːme in Italian and in Fiuman dialect, Fiuman Venetian) is the principal seaport and the List of cities and towns in Croatia, third-largest city in Croatia. It is located in Primorje-Gorski Kotar County on Kvarner Ba ...

. They had been governed from the town of

Aquileia Aquileia is an ancient Roman city in Italy, at the head of the Adriatic at the edge of the lagoons, about from the sea, on the river Natiso (modern Natisone), the course of which has changed somewhat since Roman times. Today, the city is small ( ...

Development

In the year 6 AD the

Great Illyrian Revolt The (Latin for ''War of the Batos'') or Great Illyrian Revolt was a military conflict fought in the Roman Empire, Roman province of Illyricum (Roman province), Illyricum in the 1st century AD, in which an alliance of native peoples of the two re ...

took place threatening the Roman heartland. Subsequently, in order to protect Italy, a series of walls and fortifications were gradually erected around the area of the strategic Postojna Gate. Most of the construction was done after 284 under

Diocletian Diocletian ( ; ; ; 242/245 – 311/312), nicknamed Jovius, was Roman emperor from 284 until his abdication in 305. He was born Diocles to a family of low status in the Roman province of Dalmatia (Roman province), Dalmatia. As with other Illyri ...

and

Constantine I Constantine I (27 February 27222 May 337), also known as Constantine the Great, was a Roman emperor from AD 306 to 337 and the first Roman emperor to convert to Christianity. He played a Constantine the Great and Christianity, pivotal ro ...

. Although this development was done subsequent to a major invasion of Northern Italy by the

Alemanni The Alemanni or Alamanni were a confederation of Germanic peoples, Germanic tribes * * * on the Upper Rhine River during the first millennium. First mentioned by Cassius Dio in the context of the campaign of Roman emperor Caracalla of 213 CE ...

in 271, Whittaker indicates that inner fortification lines were primarily aimed to secure the internal stability of the empire rather than keeping

barbarian A barbarian is a person or tribe of people that is perceived to be primitive, savage and warlike. Many cultures have referred to other cultures as barbarians, sometimes out of misunderstanding and sometimes out of prejudice. A "barbarian" may ...

s out. The fortification system included Forum Iulii (in the area of today's Cividale del Friuli), Tarsatica (in the area of today's

) and followed the valley of the

Idrijca The Idrijca is a river flowing through the Idrija Hills and Cerkno Hills in Slovenia. It is long. It rises near Vojsko, Idrija, Vojsko, flows towards northeast and after passing through Idrija turns to the northwest. After passing through Spodn ...

river. It stretched over the Postojna Gate to the hills south of Emona (in the area of today's

Ljubljana {{Infobox settlement , name = Ljubljana , official_name = , settlement_type = Capital city , image_skyline = {{multiple image , border = infobox , perrow = 1/2/2/1 , total_widt ...

). In-depth fortifications along the Roman road Via Gemina started at the fortress of Castra ad Fluvio Frigido (the remains of which are today still visible in

), which was the centre of the system, and ended at Nauportus (in the area of today's Vrhnika). The hill fortress of Ad Pirum was typically manned with 500 soldiers but could keep up to 100,000 soldiers. Ad Pirum’s walls were unearthed by Austrian and Italian archeologists and shown to be at a height of 8 m and a thickness of 2 m; the wall towers were 10 m high.

Battles

Claustra Alpium Iuliarum saw a number of battles. Early fortifications may have been useful in 169 when the Marcomanni attempted to enter Italy but proved inadequate when the Alemanni invaded Italy in 271. In 351

Constantius II Constantius II (; ; 7 August 317 – 3 November 361) was Roman emperor from 337 to 361. His reign saw constant warfare on the borders against the Sasanian Empire and Germanic peoples, while internally the Roman Empire went through repeated civ ...

took Ad Pirum during his fight against his challenger

Magnentius Magnus Magnentius ( 303 – 10 August 353) was a Roman general and usurper against Constantius II. Of Germanic descent, Magnentius served with distinction in Gaul, where the army chose him as a replacement for the unpopular emperor Constans. Ac ...

. Most importantly, the Battle of the Frigidus took place in 394 between Castra and Ad Pirum. In this battle the eastern emperor

Theodosius I Theodosius I ( ; 11 January 347 – 17 January 395), also known as Theodosius the Great, was Roman emperor from 379 to 395. He won two civil wars and was instrumental in establishing the Nicene Creed as the orthodox doctrine for Nicene C ...

prevailed over his western rival Eugenius and by his victory secured Christianity as the main religion of the empire. After the 5th century the Roman fortifications fell into disrepair. Today selected sections have been restored by archeologists.

References

External links

Claustra.org
Website dedicated to Claustra Alpium Iuliarum. * {{Coord, 45, 51, 49, N, 14, 6, 42, E, type:landmark_region:SI_dim:140km, display=title Roman walls Roman fortifications in Slovenia Linear earthworks

Development

Battles

Further reading

References

External links