Winter AD 121/2 – Hadrian inspects the northern frontiers: part 2 Raetia (#Hadrian1900)

After Hadrian inspected the military forces and installations in Germania Superior (see here), the Emperor visited the limes and the army troops of the neighbouring province of Raetia, now part of German Bavaria. At the time of Hadrian’s visit in AD 122, no legion was stationed in this area. Still, the province relied on its large auxiliary units of mounted alae and infantry soldiers for protection. 

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The province of Raetia was established decades after the Roman military conquest under Drusus and Tiberius in 15 BC. It occupied an area north of the Alps, with two important highways running through it, one connecting Italy with the Danube River (the Via Claudia Augusta) and the other linking Gaul with the Balkan provinces. The limes in Raetia (part of the German-Raetian Limes, inscribed on the World Heritage List) extended from Lorch in Württemberg in Germany, then ran eastward to Hienheim near Regensburg on the Danube. From Eining (the site of Roman Fort Abusina), the eastern Raetian Limes followed the Danube as a typical river frontier (ripa) as far as the mouth of the Inn in Passau on the boundary of the province of Noricum.

Military posts along the Danube first appeared in western Raetia during the reigns of Tiberius and Claudius and further downstream in the Flavian period. Under Trajan at the beginning of the 2nd century, Roman control extended beyond the Danube in western Raetia, and the limes was reinforced. Hadrian continued the policy of border security and was responsible for a remarkable boundary in the shape of a palisade in Germania Superior.

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The statement of the Historia Augusta (HA Hadr. 12.6), “in many regions where the barbarians are held back not by rivers but by artificial barriers, Hadrian shut them off using high stakes planted deep in the ground and fastened together in the manner of a palisade.” has been confirmed by the finding of the remains of stakes in stone-ballasted trenches at many points and especially at Marköbel in the Wetterau where well-preserved timbers were uncovered inside two waterlogged stretches. Tree-ring analyses showed that the trees were felled in the winter of 119/120 (Schallmayer, 2003), implying that the palisade was already under construction when Hadrian arrived in the province (read more here). 

Watchtowers, military roads, and fortified camps completed the defensive works. About thirteen of these stations, generally of earlier date, guarded the Raetian frontier, most situated a few miles inside. The Raetian-Norican river frontier was not threatened before the Marcomannic Wars during the reign of Marcus Aurelius (AD 166-180). Only then was it necessary to deploy legions there, one in each province.

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One of the most important Roman cities in the province of Raetia was Cambodunum (modern Kempten), which served as the provincial capital of Raetia throughout the 1st century AD before Augusta Vindelicum (modern Augsburg) took over this role, probably under Trajan. In 16 BC, Roman troops led by Drusus conquered the Raeti and founded the Roman city of Cambodunum with baths, a forum and temples. The town prospered in the 1st century and became a busy market town of craftsmen and merchants and the administrative seat of the governor of the province. The prosperity of Cambodunum vanished during the latter part of the 1st century owing to a shift of the east-west trade routes after the frontier was moved north of the Danube.

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Augsburg, located about 80 kilometres northwest of Munich in southern Germany, started as a military camp built under Emperor Augustus between 8 and 5 BC. The camp grew into the town of Augusta Vindelicum, which later became the capital of the Roman province of Raetia. Tacitus spoke of Augusta Vindelicorum as “a colony of the province of Raetia” (Germania, 41). During his inspection tour of the province, Hadrian granted Augusta Vindelicum a higher level of self-government by raising its status to that of a municipium and renaming it municipium Aelium Augustum (shortened to Aelia Augusta CIL XIII 6558 & 6741). 

During the 2nd century AD, the new municipium experienced a period of prosperity as a trading metropolis with up to 15,000 inhabitants. The city’s public buildings were rebuilt entirely in stone, probably in connection with Hadrian’s granting of municipal rights. Various rescue excavations have identified a few buildings, including two thermal bathhouses, a market hall with an inner courtyard, a large house with a peristyle probably from Hadrian’s time and the city walls. The entrance to the forum has also been located. The oldest layers of Roman Augsburg lie up to seven meters below the modern city’s street level, and today almost nothing remains above ground. Some archaeological finds, stone monuments and inscriptions are now displayed in the Roman Museum. An impressive mosaic floor with circus and gladiator scenes was discovered in 1571 but has since been lost and survives only on an engraving (see here). 

In 2021, archaeologists unearthed over 5,500 Roman silver coins in the Oberhausen district of Augsburg, the most significant Roman hoard ever discovered in Bavaria. The denarii range in date from the reign of Nero in the mid-1st century to that of Septimius Severus shortly after AD 200. Trajan, Hadrian, Antoninus Pius and Marcus Aurelius are also represented. They are believed to have come from the legionary camp of Augustan times. In addition to the coin hoard, archaeologists have discovered hundreds of other Roman artefacts, including weapons, tools, jewellery and vessels sifting through 1000 cubic metres of river gravel. 

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Another Raetian municipality was the town of Abodiacum (modern Epfach), the patria of Claudius Paternus Clementianus (AD 65-130), the governor of the province of Noricum until 125. He was the son of a Celtic legionnaire who received Roman citizenship from Claudius (or possibly Nero). Clementianus’ first senior administrative post had been as governor in Judea, then in Africa Proconsularis and Sardinia, ending his career as governor of Noricum (CIL 03, 05775 & 05776). Abodiacum was built as a military station on the Via Claudia Augusta.

A governor from the equestrian estate administered the small province of Raetia (Tac. Hist. 1.11), whose official residence in Hadrian’s time was at Aelia Augusta (Augsburg). The governor headed the civil and judicial administration of the province and was the commander-in-chief of all the auxiliary troops stationed there. His staff included a 500-strong escort force of cavalry and foot soldiers (equites and pedites singulares). Unfortunately, no certain Hadrianic procurators are known for Raetia.

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At the beginning of the Hadrianic era, the northern frontier of Raetia was approximately twenty-five kilometres north of the Danube and came forward to meet the river at Eining (Abusina). The Raetian army consisted entirely of auxiliaries forces, comprising 21 units stationed in fourteen auxiliary forts along the frontier, totalling 12,100 soldiers (3,000 horsemen and 9,100 infantrymen). Three new forts appear to have been established by Hadrian on the eastern section of the Alblimes at Pfünz (Castra Vetoniana), Ruffenhofen and Theilenhofen, as well as one numerus-sized fort at Ellingen (C. S. Sommer, 2012).

Based on Sommer’s reinterpretation of the archaeological evidence and dendrochronological analysis of the timber structures, the auxiliary castellum of Vetoniana at Pfünz was constructed early during Hadrian’s reign as a wood-and-earth fort. It covered an area of 2.5 hectares, with sides measuring 189 × 145 meters, and was protected by a double V-shaped ditch on three sides and a single ditch on its southern facet. Vetoniana was garrisoned by the cohors I Breucorum civium Romanorum equitata, a 500-strong infantry unit with a mounted detachment regiment of Breuci, an Illyrian tribe from Pannonia. The cohort had received Roman citizenship as a reward for bravery. It assumed the position of a rear cohort fort on the Raetian limes until its demise in 254. The fort was reconstructed in stone under Antoninus Pius (AD 138-161). 

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The Hadrianic fort at Ruffenhofen was located two kilometres south of the Danube. The fort covered an area of 3.7 hectares, with sides measuring 190 × 197 meters. Originally made with wood, the fort was rebuilt in stone in AD 150/160. It was operational until the middle of the 3rd century when it was destroyed by fire, as indicated by a thick burnt layer found amongst the ruins of the towers, the principia and the horreum. The fort was garrisoned by the cohors IX Batavorum between 118/119 and 175, an auxiliary unit of infantry and cavalry.

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At Theilenhofen, a timber fort called Iciniacum with its associated bathhouse was built around 120 as part of Hadrian’s military reorganization and expansion. At that time, its area was 2.27 hectares, with sides measuring 160 × 142 metres. The Hadrianic fort was replaced in the 160s under Marcus Aurelius by a more permanent stone structure with reinforced defences. It now covered an area of 2.82 hectares, with sides measuring 196 × 144 meters. 

The new fort was destroyed during the Germanic incursions in 254. An infantry unit, the cohors III Bracaraugustanorum equitata, to which some mounted soldiers were attached, is known from several inscriptions. Its name tells us that it was raised in Bracara Augusta, in modern-day Portugal. 

A lavishly decorated 2nd-century AD helmet was unearthed while ploughing near the fort of Theilenhofen. It is a tinned brass cavalry helmet with a large eagle sitting on top, flanked by two pouncing lions. The engravings on the helmet name up to five different owners in succession from the unit cohors III Bracaraugustanorum, showing it had a long history of use before its deposition.

Finally, a fortlet was built at Ellingen (castellum Sablonetum) around AD 120 on a small plateau around 1.8 kilometres south of the limes and in an advanced position to the military base of Weißenburg-Biriciana. It was initially built as a wood-earth construction, followed by an expansion phase with a stone wall around 182 under Emperor Commodus. The two-gate fort of ​​only 0.7 hectares (90 x 80 m) housed a numeri, a small reconnaissance and observation unit of about 130 – 150 men.

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During the reorganizations of Hadrian, two garrison units left Raetia: the cohors III Batavorum (recruited from the Batavi people) was transferred to Pannonia, and the ala I Augusta Thracum to Noricum. The latter was replaced by the ala I Flavia Gemelliana (RMD 1, 25). Furthermore, vexillationes (detachments) from two units, the cohors II Tungrorum and the cohors IV Tungrorum, were brought in from Britannia, possibly to the forts at Eining (Abusina) and Faimingen, respectively. In addition, seven units of the Raetian garrison were relocated within the province during this period, including the ala II Flavia to Heidenheim/Aquileia (IBR 00208). 

Unlike in Germania Superior, there is no evidence of a Hadrianic timber palisade system in Raetia. Such a wooden fence was established only during the military reorganization of Marcus Aurelius in the 160s. While in Germania Superior, the Romans replaced the wooden palisade with a system of banks and ditches. In the province of Raetia, the timber palisade was replaced by a stone wall nearly 3 metres high, studded with interval stone watchtowers. The cause for the erection of a stone wall could have been a problem in procuring new wood as it is likely that all large trees in the area had already been felled.

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Hadrian minted an exercitus (army) coin for Raetia with the legend EXERCITVS RAETICVS, testifying to his awareness of the province’s military importance. On the reverse, Hadrian is depicted on horseback, raising his right hand and haranguing three soldiers holding standards. Unlike Gallia, no restitutor coin was minted, and there were no milestones set up in these years documenting the renewal of the local road system.

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The Raetian limes formed the southeastern part of the artificial border of the Imperium Romanum, which stretched over 550 kilometres from Bad Hönningen on the Rhine to Regensburg on the Danube (known today as the Upper German-Rhaetian Limes). In Bavaria, the limes crossed Middle Franconia and Upper Bavaria territories, ending at the banks of the river Danube in Eining in Lower Bavaria. Around 180 watchtowers secured the 166 kilometres (103 mi) of the Raetian limes by the 3rd century AD. Subsequently, ten fortlets were built to guard key locations like road crossings, rivers, and steep valleys.

In 1861, the Bavarian King Maximilian II erected a memorial stone near Hienheim in Bavaria, the so-called Hadrian’s Column (“Hadrianssäule”), to mark the beginning of the Limes along the Danube. The inscription on the column names the Emperors Hadrian and Probus as erectors of the Limes. It reads:

Hier am linken Donauufer beginnt der von den römischen Kaisern Trajan, Hadrian und Probus in den Jahren 117 bis 282 n.Chr. gegen die Teutschen angelegte bis an den Rhein laufende Wall auch Teufelsmauer genannt.

English translation: Here on the left bank of the Danube begins the wall built up to the Rhine against the Germans by the Roman emperors Trajan, Hadrian and Probus in the years AD 117 to 282.

Hadrian would later inspect the fortifications and troops in the neighbouring province of Noricum, where he would raise several Norican communities to the status of municipium.

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Sources & references:

• Birley, Anthony R., (1997). Hadrian. The restless emperor, Routledge London New York pp. 113-122
• C. Sebastian Sommer: Trajan, Hadrian, Antoninus Pius, Marc Aurel …? – Zur Datierung der Anlagen des Raetischen Limes. In: Bericht der Bayerischen Bodendenkmalpflege. Band 56, 2015, S. 321–327, hier S. 142.
• Fraser. Trudie E. (2006). Hadrian as Builder and Benefactor in the Western Provinces. BAR International Series 1484.
• Farkas István Gergő: The Roman Army in Raetia Dissertation, University of Pécs Faculty of Humanities, 2015
• Breeze, David J. The Frontiers of Imperial Rome. Pen and Sword Military, 2019.
• Martin Kemkes. “Chapter 7/The Limes.” The Oxford Handbook of the Archaeology of Roman Germany, edited by James, Simon & Krmnicek, Stefan. Oxford University Press, 2020.

Links:

• A Visitor’s Guide to Rome’s Frontier in Germany
• Limes photo collection
• Deutsche Limes-Straße
• The Limes in Germany (video)
• Frontiers of the Roman Empire (video)

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