The Castra Alteium () is a former late-Roman border fort on the Danube-Iller-Rhine Limes (DIRL). It is located in the territory of the city of Alzey in Rhenish Hesse, Germany. The fort was presumably built in the course of the last reconstruction measures on the Rhine frontier between 367 and 370 AD under the western Emperor Valentinian I. Previously, there was a Roman civilian settlement (Vicus), Altiaia, which was devastated by Alamanni in 352–353. The fort was also destroyed twice, and probably abandoned at the end of the fifth century.
Name The ancient place name Altiaia possibly goes back to a pre-Roman Celtic settlement from 400 BC. The Roman name appears for the first time on the dedication inscription: In h(onorem) d(omus) d(ivinae) / d(eabus) Nymphis / vicani Al/tiaienses aram posuer(unt) / cura Octoni / Terti et Castoni / Cassi X K(alendas) Dec(embres) / Maximo et Aeliano co(n)s(ulibus). Translation: "In honor of the divine imperial house the inhabitants of Altitaia erected this altar under the direction of Octonius Tertius and Castonius Cassius, ten days before the Kalends of December (22. November) in the consulate of Maximus and Aelianus." The two consults held office in 223 AD. of a Nymphaeum reused in the fort wall. The inscription, identifying the population as vicani Altiaienses, and the town as vicus Altiaiensium or vicus Altiaiensis is datable to the year 223. The meaning of the name can no longer be determined today. The late antique Alteium (or Altinum ) is mentioned only in Codex Theodosianus and is almost certainly derived from the name of the civil settlement. In the Codex the place is once referred to as Alteio and the other time again as Altino.
Location and purpose The town of Alzey is located in German federal state of Rhineland-Palatinate on the western edge of the northern part of the Upper-Rhine Valley (Oberrheinischen Tiefebene) on the left side of the Rhine, about from it. It is surrounded by the northern part of the Alzey hill country, which is adjoined to the north by the Rheinhessisches Hügelland and to the west by the Nordpfälzer Bergland. The town is located about southwest of Mainz and about northwest of Worms. Through Alzey flows, partly underground, a section of the Selz, a left tributary of the Rhine. The narrow Selz valley begins to widen from Alzey to the north. The Roman civilian settlement was part of the province of Germania Superior and was governed from the provincial capital of Mogontiacum (Mainz). After the administrative reforms of Diocletian Castra Alteium was located within the territory of the new province of Germania Prima in the southwestern area of the former vicus, on a southern spur of the Mehlberg mountain on a steep slope to Selz. From here the garrison had a good view of the surrounding area, especially to the north.
The fort probably protected and monitored a crossing over the Selz and the junction of the road links Mainz-Alzey-Metz and Bingen-Kreuznach-Alzey-Worms. However, the camp was possibly used primarily for the temporary accommodation of units of the mobile field army (Comitatenses), because there was otherwise little accommodation in the hinterland of Mogontiacum for larger troop contingents. In an emergency, the central plaza could also accommodate tents to quarter additional troops.Jürgen Oldenstein: 2009, S. 15, 259 und 265.
Research history Datable finds of the vicus date back to the middle of the 4th century AD. The first known reports on Roman finds were written in 1783 by the pastor of Dautenheim, Johann Philipp Walther, who excavated old foundations on a church-owned field (presumably the remains of the eastern wall of the fort) and discovered three Roman inscriptions. In 1869, the Mainzer Altertumsmuseum acquired late-antique or early medieval finds from Alzey— a pair of gilded-silver crossbow brooches, a silver needle, earrings, two small disc brooches with almandine inlay, and pendants, each richly decorated with golden filigree wire. Such crossbow brooches were worn only in pairs at the shoulders. Together with two small brooches, such as small disc brooches, they formed the "vierfibeltracht" which was typical of the women's fashion in the 6th century. In the 1870s the teacher Gustav Schwabe presented a collection of Roman finds, which were later lost. In 1871/1872 a votive altar to the goddess Sulis came to light in the north wall. Another altar found in Alzey was dedicated to Fortuna. Another example was dedicated to Minerva by the fuller Vitalianus Secundinus. In the foundations of the late antique church building in the fort they encountered fragments (spolia) of a gateway, which was probably originally erected in a place of worship of the god of the springs Apollo-Grannus, probably the sulfur spring at today's tax office., Wolfgang Diehl, 1981, S. 17-18.
In 1902 the section commissar of the Reichs-Limeskommission (RLK), Karl Schuhmacher (1860-1934), and the local historian Jakob Curschmann (1874-1953), identified a part of the wall and the foundations of a round tower at the southwest corner. Nursery owner Jean Braun, then the owner of the fort and later co-founder of the Alzey Museum, continued to investigate and discovered further remains of the wall on the west side. By 1904, during construction, further remains of the fort wall and, at the cemetery of the former St. George's Church, ancient sandstone slabs and sarcophagus components came to light. In 1904, the preservationist Soltan dug large parts of the eastern wall. The east gate was only very poorly preserved; it could only be stated that the gate towers extended behind and in front of the wall. In 1906, further foundations of the fort were discovered and partially restored.
In 1909, the prehistorian Eduard Anthes (1859-1922) took over the supervision of the excavations, supported by the district and city of Alzey, the Historical Association of the Grand Duchy of Hesse, and the Römisch-Germanischen Kommission excavations. In the same year Braun also discovered the west gate, whose passage was mostly filled with rubble. The southeastern corner tower was of high structural quality and its existing masonry still exhibited several courses. On the south wall, Braun discovered two well-preserved rooms of a barracks attached to the castle wall. The two rooms were dug to a depth of . At the bottom of the eastern chamber many animal bones were found; presumably this part of the building served as a slaughterhouse. In the western iron fragments and tools as well as two stones which may have served as anvils were uncovered. In front of the building was a well shaft covered with sandstone slabs. By 1909, about of the perimeter wall had been uncovered. At most of the sites examined it was only below the surface. Their rising masonry was still partially preserved up to a height of . In 1925, the prehistorian Wilhelm Unverzagt (1892-1971) succeeded in finding the so-called "Alzey burn layer" which marked the end of the second settlement phase of the fort. Above this layer mainly ceramics of the late 4th century AD were recovered. The complex of migration period ceramics from the excavations is still used in research today as a tool to date other sites of this era. Several excavation campaigns in the fort area were also conducted by the Institut für Vor- und Frühgeschichte of the Johannes Gutenberg University of Mainz.
Finds For the dating of the fort mainly the coin finds and a brick temple of the Legio XXII Primigenia were important. The objects found in the excavation area, mainly Roman glassware and ceramics, give some information about the origin of the fort's inhabitants. Noteworthy in this context is a comb with a bell-shaped handle, which was widespread among the East Germanic peoples. Other comb types from Alzey come from Elbe Germanic regions. Half-round, serrated belt buckle plates of the "Muthmannsdorf" type have been mainly observed on the Danube and in the Elbe and eastern Germanic areas, but provincial Roman types are also represented. In 1929 a 5 x 11.5 cm limestone slab with three engraved busts and two Christ monograms was discovered in the southeast corner of the fort. Also found was an early Christian bread stamp from the 4th century used to stamp the eucharistic bread.. The discovery of Spiral fibulae of the "Mildenberg" type, which did not originate before 440 AD, marks the Alamannic settlement phase of the fort.Claudia Theune: Germanen und Romanen in der Alamannia. Strukturveränderungen aufgrund der archäologischen Quellen vom 3. bis zum 7. Jahrhundert. (= Ergänzungsbände zum Reallexikon der germanischen Altertumskunde, Band 45) de Gruyter, Berlin 2004, , S. 412.
Development The mild climate, the rolling hills and fertile loess soil made the region attractive for settlers from an early period. The first signs of settlement in the Alzey area can already be found from the Neolithic period (Linear Pottery culture). Later, peoples of the Michelsberg culture settled here. Towards the end of the 2nd millennium BC. Illyrians (Urnfield culture) immigrated to the area around Alzey. From the early La Tène period the Alzey region was populated by Celts. When the Romans occupied the region around the year 50 BC. they found a small late La Tène settlement, which was probably inhabited by members of the Treveri and Mediomatrici tribes. There was probably a Celtic settlement on the Selz ford at the intersection of two busy trackways. Possibly the inhabitants also exploited the nearby sulfur springs.Jürgen Oldenstein: 2009, S. 12, Wolfgang Diehl, 1981, S. 15.
With the conquest of Gaul by Julius Caesar the border of the Roman Empire was advanced to the Rhine. Legionary camps were built in Bingen, Mainz and Worms during the Augustan Age. The Celtic settlements were followed by the Roman Vicus Altiaia, which was founded around the middle of the first century BC. In addition to the limes road, which ran along the Rhine, there was another road connection which led from Worms to Bonn via Alzey. Under Trajan the region around Alzey experienced its economic and cultural heyday. Numerous estates, such as the Roman villa of Wachenheim, supplied the border garrisons with food.Wolfgang Diehl, 1981, S. 16-17
Altaia was burnt by the Alemanni under Chnodomar in the middle of the 4th century AD (352/353). In 370, in the course of the last Roman reinforcements on the Rhine Limes, the late antique Castrum Alteium was built on the ruins of the civilian settlement. The fort's name is mentioned in connection with two visits of Emperor Valentinian I, in 370 and 373, who probably issued some laws or rescripts here. No evidence of an earlier military facility could be detected. Despite the intricately constructed defenses, the fortress was, according to coin finds, only occupied by Roman troops for a few years. It may have been completely vacated as early as 383 in the wake of the usurpation of British governor Magnus Maximus, when the western emperor, Gratian, assembled troops near Lutetia (Paris) to oppose him. Most likely, the garrison of Altaia were also part of Maximus' army, with which, in 388, he fought the eastern Emperor Theodosius I at the Battle of the Save at Siscia and Poetovio.