Mogontiacum (also Moguntiacum) is the Latin name of today's city of Mainz, which it bore during its almost 500 years as part of the Roman Empire. Mogontiacum had its origins in the legionary camp built by Drusus in 13/12 BCE, which was strategically located on a above the Rhine and opposite the mouth of the Main on the .
The civilian settlements (vici) in the vicinity of the camp, which spread down the Rhine, quickly grew together to form a larger, urbanised settlement. However, unlike Colonia Claudia Ara Agrippinensium (Cologne) or Augusta Treverorum (Trier), Mogontiacum was primarily a military centre until the second half of the 4th century and was apparently not a colonia either. As a result, it never had the urban character of the other large Roman cities in Germany. Nevertheless, several monumental buildings were also erected here, as Mogontiacum was the provincial capital of the Roman province of Germania Superior with the seat of the governor as of the year 90 at the latest. After the middle of the 3rd century, when the Romans evacuated the Decumatian Fields, Mogontiacum once again became a border town and was devastated several times over the next 150 years by members of various Germanic peoples. After the end of the Roman period, but at the latest around 470, Mogontiacum belonged to the Frankish Kingdom after a brief transitional phase.
Some important remains of Mogontiacum have been preserved in the present-day city of Mainz, for example the Roman stage theatre, the Great Mainz Jupiter Column, the Drusus Stone and the , remains of the aqueduct of the legionary camp. The Roman-Germanic Central Museum, the Mainz State Museum and the Museum of Ancient Seafaring preserve numerous artefacts from Roman rule in Mainz.
Naming
The name Mogontiacum is composed of the Celtic name Mogo(n), the Celtic suffix -ontiu- (as in Vesontio/Besançon) and the affiliation suffix *-āko, Latinised to .; It thus contains the name of the Celtic god Mogon as a component. The name could have been derived from a Celtic settlement of the Aresaces, a section of the Treveri people, located in the immediate vicinity of the legionary camp. These were located at the end of the first century BCE in the area of today's Mainz-Weisenau and . Mogontiacum was first mentioned in historiography by the Roman historian Tacitus in his work Histories, written at the beginning of the 2nd century, in connection with the Revolt of the Batavi. The derived spelling Moguntiacum is also common. Abbreviations and different spellings were also common at the time of Roman rule. For example, Moguntiacum was abbreviated to Moguntiaco in the Tabula Peutingeriana. Epigraphically, the city name is first documented on a milestone from the Claudian period.
History The almost 500-year Roman history of Mogontiacum can be divided into four simplified periods: The first period begins with the founding of the city towards the end of the 1st century BCE and ends with the establishment of the province of Germania superior and the appointment of Mogontiacum as the provincial capital. The period between 90 CE and 260 CE covers the city's golden age until the fall of the Limes, when Mogontiacum once again became a border town of the Roman Empire. In the third period, from 260 to 350 CE, the city underwent profound changes in the face of internal turbulence in the Roman Empire and the growing threat from Germanic warriors. The final period from 350 CE to 470 CE reflects the decline of the city, which was plundered and devastated several times.
Foundation of Mogontiacum and history until Domitian (13/12 BCE to 90) In the course of Augustus' expansionist endeavours starting in 16 BCE, his stepson Nero Claudius Drusus also advanced to the Middle Rhine and secured the area for the Roman Empire. By 13/12 BCE at the latest, possibly earlier, a double legionary camp was established on a hill above the Rhine and opposite the mouth of the Main. The military presence of the Romans at this location primarily secured their control over the Middle Rhine, the mouth of the Main and generally over the Main as one of the main routes into free Germania.
At the same time, another military camp was built just four kilometres south of today's Mainz district of Weisenau. This was mainly occupied by auxiliary troops, but was also used temporarily for the stationing of other legionaries. This was also the site of one of the late Latène Celtic settlements in the Mainz area. The local Celtic population belonged to the Aresaces, a section of the Gallic Treveri, who were located here in their settlement area furthest to the east.
Until the annexation plans were abandoned in 16 BCE, Mogontiacum served several times as a base for military operations as part of the Drusus campaigns (12 to 8 BCE), the campaign against the kingdom of Marbod (6 CE) and the Germanicus campaigns (14 to 16 CE) in Germania on the eastern side of the Rhine. Shortly afterwards, legionaries in Mogontiacum erected a cenotaph in the immediate vicinity of their camp to honor Drusus, who had died in 9 BCE. This monument is probably identical to the Drusus Stone on the Mainz citadel that still exists today. As early as the time of Drusus, a ship bridge was built above the mouth of the Main to cross the Rhine. In the first decade of the 1st century BCE, the bridgehead Castellum (Castellum Mattiacorum) on the right bank of the Rhine was founded and expanded, which became the nucleus of today's Mainz-Kastel (derived from the Latin castellum). The construction of a fixed wooden bridge (pile bridge) between Mogontiacum and Castellum can be dated to the year 27.
After the reorganisation of the Roman Rhine army into an Upper and a Lower Germanic army in the year 17, Mogontiacum became the seat of the commander of the Upper Germanic army. In addition to the rapidly forming camp suburbs (canabae legionis) in the south and south-west of the legionary camp, various civilian settlements (vici) developed, which stretched eastwards down to the Rhine and possibly slowly merged into a coherent settlement structure during the course of the 1st century. In the first half of the 1st century, Mogontiacum already had large civilian buildings with a large public thermal bath complex and a theatre mentioned by the Roman writer Suetonius. The Great Column of Jupiter in Mainz, dated to the third quarter of the 1st century, was donated by an apparently wealthy larger civilian community and can be seen as evidence of the rapid progress of Mogontiacum's civilian development. Despite the beginning development of civilian structures, Mogontiacum remained one of the most important military bases of the Roman army on the Rhine. Two legions, including auxiliaries and baggage train, were permanently stationed in Mogontiacum and in the second military camp in Weisenau, which had been expanded since the reign of Caligula. Additional troops were stationed as required - for example, after the Varus Battle, when three legions were temporarily stationed in Mogontiacum.
During the Revolt of the Batavi, most of the civilian buildings outside the legionary camp were destroyed. According to Tacitus, the camp itself was besieged without success. Under the rule of the Flavian imperial family, extensive building work was carried out in Mogontiacum. Vespasian had the legionary camp rebuilt in stone, and likewise sponsored new stone piers for the pile bridge. During the reign of Emperor Domitian, a stone aqueduct replaced its wooden predecessor. The aqueduct carried fresh water over a distance of nine kilometres from the springs in today's distant Mainz districts of (Fontanetum) and Drais to the legionary camp on the Kästrich.
In 83, the city was the starting point for Emperor Domitian's campaign against the Chatti. To this end, he assembled an army of five legions and auxiliary troops in Mogontiacum. In 88 and 89, the governor Lucius Antonius Saturninus revolted in Mogontiacum. After the rapid suppression, the military territory was transformed into the province of Germania superior with Mogontiacum as the provincial capital (caput provinciae), which had already been planned beforehand and was thus finalised.
Provincial capital and important military centre on the Rhine (90 to 260) The process of transforming the military territory into the province of Germania superior began in the mid-80s of the 1st century and was fully completed by the middle of the year 90 at the latest. A military diplomaState Museum Mainz Inv. no. 0.400, dated 27 October 90 is considered the earliest epigraphic evidence of the newly established province. With Lucius Javolenus Priscus, the province was given a consular governor who was already experienced as a suffect consul and who quickly developed the necessary civil structures. Beginning under Domitian and continuing under his successors, the Romans secured areas on the right bank of the Rhine to protect the new provinces and consolidate their territory. With the permanent occupation of the , the Taunus and the Wetterau, the Upper Germanic-Rhaetian Limes was created. Mogontiacum now assumed the important role of military administrative centre for the Upper Germanic section of the Limes until its downfall.
There were also lasting changes for Mogontiacum itself: As a result of the experiences of Saturninus' revolt, the number of permanently stationed legions was reduced from two to one. From the year 92, this was the Legio XXII Primigenia, which from then on remained the sole legion of Mainz until its defeat in the middle of the 4th century. From 96 to 98, the later Emperor Trajan held the office of governor of the province; Hadrian, his successor, had also been stationed there as part of his previous career as a military tribune. A time of peace and prosperity dawned for Mogontiacum. The border with free Germania was far advanced and secured by the increasingly elaborate Limes. Trade and crafts flourished in the city and throughout the surrounding area, where many veterans of the military troops settled. The invasion of the Rhine-Main region by the Chatti in 162 and again in 169, as well as the crossing of the Rhine, remained one-off events for the time being without any major impact.
It would take until 19(?) March 235 for Mogontiacum to once again become the focus of Roman world history. As part of the preparations for a campaign against the Alemanni, Emperor Severus Alexander gathered troops in Mogontiacum. There he and his mother Julia Mamaea were murdered by Roman legionaries during riots in or near Mogontiacum in the vicus Britannicus (?). This was immediately followed by the proclamation of the military commander Gaius Iulius Verus Maximinus (with the later acquired epithet Thrax) as his successor. This was the beginning of the era of the soldier emperors, which also coincided with the imperial crisis of the 3rd century.
Around the year 250 or a little later, the civilian settlement on the Rhine was surrounded by a city wall. This enclosed the entire previously populated area as well as the large stage theatre, but not the camp canabae to the southwest. This first city wall extended to the fortified legionary camp in the south-west of the city, which supplemented the city wall at this point with its own fortifications. As the so-called Limesfall is generally dated to the year 259/260, the two events are not directly connected, as previously assumed. Rather, the presence of Roman troops, who repeatedly had to deploy large detachments for campaigns in distant areas and were distracted by a series of civil wars, was probably no longer considered sufficient to protect the city against raiders. With the abandonment of the Upper Germanic Limes, Mogontiacum once again became a border town - despite further use of areas on the right bank of the Rhine, such as the Castellum bridgehead or the thermal baths in neighbouring (Wiesbaden).