The city of Mainz has Roman origins and can look back on over 2,000 years of history. Founded as the Roman legion camp Mogontiacum, the city later became the capital of the province of Germania superior and was the seat of the archbishop from 780/82 to 1803. The city experienced its heyday between 1244 and 1462, when it was a free city. After that, its history was shaped by the Electors and Archbishops of Mainz, who resided in the city, until the end of the 18th century. After this era, Mainz largely lost its importance as a federal fortress, while its role as a fortress increased. In 1946, Mainz became the capital of Rhineland-Palatinate. Background Human life in the area around present-day Mainz has been documented as far back as 20,000 to 25,000 years ago. In 1921, a hunting camp dating back to the last Ice Age was uncovered on Mainz's Linsenberg hill. This important relic has been recorded in specialist literature and is the oldest trace of human life in the Mainz area.
Due to the Rhine River, which has been the city's lifeline since its inception, a rich cultural and ethnic life flourished in the area now known as Mainz after the end of the Stone Age, particularly around 1800 BC, continuing through the Bronze Age and all subsequent eras. In the second half of the 1st millennium BC, the Celts were the dominant power in the Upper Rhine region. They also settled in the Mainz area and named this settlement, which was not comparable to a city, after one of their gods, Mogon. The Romans who arrived later derived the city name Mogontiacum from this name, which was first mentioned by Tacitus.
In 75 BC, the Germanic tribes under the leadership of Ariovistus arrived near Mainz, where they crossed the Rhine toward Gaul. The Celts who had been living on the Middle Rhine until then were pushed back, although in the Mainz area, which belonged to the outer sphere of influence of the Celtic Treveri tribe, the proportion of the Celtic population remained relatively intact until the arrival of the Romans.
After the Gallic Wars, which ended with the Battle of Alesia in 52 BC, the Roman Empire under Julius Caesar and later Augustus turned its attention to the Rhine and Germania. The Romans first conquered the areas on the left bank of the Rhine to subjugate Germania Magna on the right bank. One of the camps built on the Rhine as part of this plan was Mogontiacum, founded in 13/12 BC by Nero Claudius Drusus. The city is therefore one of the oldest in Germany.
Roman period
Mogontiacum belonged to the Roman Empire for nearly 500 years. An earlier date given for the founding of the legionary camp in 38 BC cannot be verified archaeologically and is no longer tenable today. Nevertheless, it was officially used as the occasion for the two-thousandth anniversary celebrations in 1962. The reliably dated beginning of Roman history in Mainz is set at 13/12 BC. As part of the Roman Empire's expansion policy toward Germania, a legionary camp was established at the mouth of the Main near Mainz at this time, and Roman rule was permanently established as far as the Rhine. Nero Claudius Drusus was responsible for this until his death in 9 BC.
Until 90 AD, only two legions were permanently stationed in the camp (starting with the 14th Legion Gemina and the 16th Legion Gallica), later one legion (22nd Legion Primigenia Pia Fidelis, the Mainz "house legion" until the middle of the 4th century AD). In preparation for various campaigns in Germania, up to four legions and auxiliary troops were temporarily stationed in Mainz. Some of these additional troops were housed in a second large military camp, which existed until the end of the 1st century AD. It was located near Weisenau on the site of today's quarry and can no longer be traced archaeologically. As a result, the military base Mogontiacum also attracted traders, craftsmen, and innkeepers. However, the people living around the camp had no civil rights and were dependent on the commandant of the camp. The main camp, which is still remembered in the name of the present-day district Kästrich (Castrum), was structured like other Roman camps: two intersecting roads (Via praetoria, Via principalis, Via decumana) with four gates (Porta praetoria, Porta decumana, Porta principalis dextra, Porta principalis sinistra).
After the disaster in the Battle of the Teutoburg Forest in 9 AD, the Rhine became the border river between Germania and the Empire. In 89 AD, after the suppression of the Saturninus uprising, the city became not only the most important military camp on the Rhine border but also the civil administrative centre and capital of the newly formed province of Germania superior (Upper Germania). The province stretched from the Upper Rhine to Koblenz, then called Confluentes. To the north lay the province of Germania Inferior with Colonia Claudia Ara Agrippinensium (Cologne) as its provincial capital. A comprehensive building program, especially by the Flavian imperial family (expansion of the legionary camp in stone, aqueduct construction, permanent pile bridge with massive stone piers), as well as the conquest of the Wetterau and the beginning of the construction of the Limes there, characterized the development of Mogontiacum in the 1st century AD.
Mainz subsequently flourished, but as a civilian settlement, it never achieved the status of Cologne or Trier. Trade routes, for example, to Divodurum (Metz), made the city prosperous. However, from the end of the 2nd century AD, the city and its surroundings were increasingly threatened by invading tribes such as the Chatti, Alamanni, and Vandals, especially after the fall of the Limes in 258 AD.
This led to the loss of the Limes territory on the right bank of the Rhine in 259/260 AD, and Mogontiacum once again became a border town. Christianity also arrived in the city in the third or fourth century at the latest. By 368, there is evidence of a bishop in the city.
However, during the same century, the decline of the Roman Empire became increasingly apparent. The Alamanni, in particular, threatened Mainz and occupied the city in 352/355. Further invasions are documented in 357, 368, and 370. Julian recaptured the city from the Alamanni in 357 AD and reinforced the Rhine fleet in Mainz (Roman ships). The city wall, which had been built in the 3rd century AD, was also rebuilt and renovated in the second half of the 4th century. On New Year's Eve 407, the Vandals conquered the city and destroyed it. In 451, the Huns invaded, but according to the latest research, they did not cause much damage in Mainz. However, this marked the end of Roman Mainz. The Franks took over and incorporated Mainz into their empire at the end of the 5th century.
Merovingians, Carolingians, and Ottonians
Toward the end of the 5th century, a battle broke out between the Franks and the Alamanni, the second-largest tribe in the region, for supremacy over the former Roman territories. In 496/97, the Frankish king Clovis I of the Merovingian dynasty was baptised after taking a vow. Clovis subsequently drove the Alamanni out of the region. He became king of West Francia and Gaul, and later also of the Frankish Empire in Cologne, which presumably included Mainz. Mainz thus became part of a large Frankish empire and developed from a border town into an inner city. From this time onward, but especially during the time of Bishop Sidonius (6th century), Christianity flourished in the city, and construction work began again for the first time. The 7th and 8th centuries saw the beginning of missionary work by Benedictine monks from the Anglo-Saxon region. The most important of these missionaries was Boniface, the missionary archbishop from Wessex. In 744, he deposed Gewilius, who was deemed unworthy due to his practice of blood feuds, and became bishop of Mainz himself, from where he initiated the Christianization of Hesse and Friesland. Under his successor, Lullus (Lul), the bishopric was elevated to an archbishopric around 780/782. The Church of Mainz developed into the largest ecclesiastical province north of the Alps, which also emphasised the importance of the city itself.
The great era of the Carolingians began with Charlemagne. Charlemagne founded one of his imperial palaces near Mainz in Ingelheim. The discovery of a fragment of a Carolingian throne from the second half of the 8th century suggests that there was also an imperial palace in Mainz. Charlemagne held several assemblies in Mainz, a tradition that continued for centuries and reached its peak in 1184 under Emperor Frederick I Barbarossa. Mainz was an ideal venue for conferences as it had a large church (75 meters long) in the St. Alban monastery near Mainz, which could be used for meetings and thus became the spiritual centre of the diocese over the next 200 years. Since Mainz had been actively promoting the Christianization of the Slavs and other Eastern peoples since the time of Boniface, it continued to develop into an important hub of the empire. This was true not only for political and religious matters but also for economic interests. Merchants, in particular, made Mainz prosperous. However, the focus of urban development always remained on religious significance, which was derived primarily from the respective archbishops. Among the early successors of Lullus, Rabanus Maurus, who came from Mainz and became archbishop in 847, is particularly noteworthy. His pontificate was the first high point in this development into an important spiritual centre. After overcoming the Norman invasions in the 9th century, the 10th century marked the beginning of the era for which Mainz owes its honorary name Aurea Moguntia ("Golden Mainz"). From then on, the archbishop bore the title "Archbishop of the Holy See of Mainz," a special honorary title held today only by Mainz and the See of Rome. Mainz became the seat of the Pope's representative beyond the Alps.
In 975, Willigis, the most important churchman of his time, became archbishop. He was appointed Imperial Archchancellor of the Holy Roman Empire of the German Nation and permanently linked this dignity to the archbishopric of Mainz. He was a key figure during the Ottonian period, whose imperial church system promoted the ecclesiastical provinces and their senior clergy. From 991 to 994, Willigis was guardian of the minor Otto III and regent of the empire, uniting the highest secular and spiritual power in Mainz; the resulting tribute payments made Mainz one of the richest bishoprics of its time. Willigis also had the great Romanesque cathedral built, which was to become the state cathedral of the empire as a manifestation of his self-image. It still dominates the cityscape and urban planning today. Mainz is referred to in historical writings of the time as Diadema regni ("crown of the empire") and Aureum caput regni ("golden head of the empire").
Archbishop Willigis completed a process that had begun in the early 9th century, making the Archbishop of Mainz the head of the city. He appointed a city count (later burgrave) to administer the city on his behalf. Mainz became an archepiscopal metropolis and remained so, with the exception of the period from 1244 to 1462, until the end of the Holy Roman Empire.
High Middle Ages