Roman Castle Unterböbingen

The fort of Unterböbingen is a former Roman fort, which today lies in the east of the municipality of Böbingen an der Rems in the Ostalbkreis in Baden-Württemberg. The cohort fort was built near the south bank of the Rems to secure the nearby Raetian Limes, which was declared a UNESCO World Heritage Site in 2005.

The complex was built on an elevated spur above the south bank of the Rems, skillfully utilizing the terrain. While the terrain rises to around 446 meters above sea level to the southeast, it slopes down to the west into the valley of the Klotzbach, which flows into the Rems river below the fort, flowing here from east to west. From the fort, the Limes running north on the heights above the Rems valley could be partially seen directly, because west of the fortification, the Raetian Wall, coming from the west, descends steeply into the Rems valley without regard for the terrain, then gently bends northeast and climbs back up the heights. In total, the garrison of Unterböbingen could monitor around 20 Limes towers along a stretch of 15 kilometers between Herlikofen in the west and Kolbenberg in the east.

Attested by the field name "Bürgle", the knowledge of an old fortification at this location seems never to have completely vanished. During initial excavations in 1885 and in the autumn of 1886 by the retired Chief of General Staff of the Württemberg army, Eduard von Kallée, Unterböbingen was recognized as a fort site and investigated in 1892 by Major Heinrich Steimle on behalf of the Imperial Limes Commission (RLK). This secured valuable results for the future, as between 1930 and 1935, the Praetentura (front camp), including the large multi-purpose hall belonging to the headquarters building, was destroyed by quarrying to extract gravel for road construction. Since no further investigations could take place in this area before its destruction, many questions remain unanswered.

The remaining parts of the fort were extensively investigated in the spring and summer of 1973 by the State Office for Monument Preservation Baden-Württemberg, Department of Archaeological Heritage, under the direction of Dieter Planck, before extensive overbuilding and the associated loss of this ancient site began. In 1975, during an excavation, larger parts of the civilian settlement with a probable road station were investigated, before historical findings here were also finally destroyed. In 1978, the excavators returned. An area already investigated in 1885/86 and 1892, where a temple stood, had to be re-examined in 1981, as it had been planned by the municipality of Böbingen for the construction of a hall.

The fort was built due to the relocation of the Alblimes to the Rems valley area. As dendrochronological investigations on and near the Limes palisade in the Rotenbachtal near the small fort of Kleindeinbach, as well as in western Schwabsberg, show, the border expansion took place around the mid-160s AD. The troops needed for the palisade construction must therefore have established their camps several years earlier. Unterböbingen was co-administered from the fort of Aalen. Due to the destructions, particularly in the 20th century, significant parts of Böbingen's antiquity have been lost.

Fortifications

The structure was built directly on a natural rock plate, which allowed for some special findings. Clearly distinguishable construction phases could not be determined. The fort was built in an approximate south-north orientation. The praetorial front, i.e., the defensive wall facing the enemy, thus stood in the north and was oriented towards the course of the Limes on the opposite side of the Rems valley. The complex enclosed a rectangular area of 148 × 135 meters (= approx. 2 ha) with its 1.2-meter-wide defensive walls (playing card shape) rounded at the corners. Following the usual structure of its time, it had four gates, each flanked by two gate towers. While the Porta principalis sinistra (here: west gate) and the Porta principalis dextra (here: east gate) each had two passages, only a single-lane access could be found at the rear Porta decumana (here: south gate). Of the Porta praetoria, centrally placed in the praetorial front, only the 4.475-meter-wide east tower remained. The still discernible ground-level tower accesses had a width of 2 meters. At the west gate, the southern gate passage was apparently walled up at some point. A similar finding was also made at the west gate of the fort of Pfünz. Both in the four corners, where a trapezoidal tower stood in each, and in the Retentura, the rear part of the camp, a rectangular tower could be identified on both the western and eastern long sides. All towers had been built leaning against the wall. Herringbone masonry (Opus spicatum) was found on the southeastern corner tower and the eastern intermediate tower. It is debated whether rectangular foundations on the fort wall could have been artillery towers. This includes a square of masonry in Unterböbingen, built directly next to the northwest tower on the praetorial front. As a special feature, at least three eight-meter-wide pointed ditches, which surrounded the camp as an approach obstacle, were cut into the bedrock.

Internal Buildings

At the intersection of the two main fort axes, inside the complex, where the two main camp roads Via principalis and Via praetoria crossed, was the large, 57.40 × 16 meter multi-purpose hall of the barracks, lying transversely across the Via Principalis, with the rooms of the Principia, the headquarters building, adjoining behind it in a square. The service and administrative rooms of this building were arranged around a rectangular, colonnaded courtyard. The rear rooms, at least three of which were heated, lay to the right and left of the flag sanctuary (Aedes principiorum) centrally located in the Principia. With its semicircular apse, the sanctuary protruded from the rear wall of the headquarters building. The design of the sanctuary with semicircular apses only became common in the forts of the Germanic provinces from the mid-2nd century. Built to the west of the headquarters building and following its long side, the Horreum, the granary, was excavated, its floors resting on stone pillars. To the east was the Praetorium, the living quarters of the camp commander, which was only partially built in timber. Those rooms that were heated were constructed in stone. The rooms standing on a massive foundation are apparently to be interpreted as the house's bath. Two of the rooms were heated, the eastern area with an apse could be interpreted as a cold bath (Frigidarium). Since stone robbing was very intensive, some findings could not be clearly identified. Research was able to locate another stone building, which was in the eastern part of the Praetentura, the rear camp area. The actual attribution of this structure, known as "Baracke" (barracks), remains unknown, however, as it was destroyed in the 1930s during quarrying. The RLK was able to identify remains of burnt timber structures under the "Baracke". In the Retentura, an underground drainage channel (Cloaca) cut into the bedrock was uncovered along the Via sagularis (camp ring road), which drained south of the southeastern corner tower into the innermost pointed ditch. This channel contained important small finds. Researchers concluded, based on a layer of burning in the area of the Horreum and Principia, that Unterböbingen met a violent end.

Finds

Among other finds from the fort area in 1973, fibulae, coins, a silver spoon, the gilded letter of an inscription, military belt fittings decorated with openwork technique, parts of horse harnesses, and the bronze thumb of a larger-than-life armored statue, probably depicting an emperor, are worth mentioning. From the Praetentura comes a fragment of a bronze military diploma, which, however, can no longer be precisely dated. Nevertheless, research places it in the first half of the 2nd century AD.

A four-inch high Roman bronze figure was found in the fort in the past but has long been considered lost. Today, an excellently preserved bronze Jupiter statuette, found in 1926, is among the significant finds. The 11.8-centimeter-high figure was recovered from the gravel of the Rems eleven kilometers below Unterböbingen. Whether Jupiter also comes from the fort, or like the Mars recovered in 1962 (see below) is to be assigned to the camp village, remains unknown.