Mainz flourished economically during the Merovingian period. Several noble families can be attested. The mintmaster Nantaharius, who minted official Merovingian gold coins in Mainz and signed them with his name, may have come from one of these families. A gold coin of the mintmaster Martinus was found in Lincolnshire in England, illustrating international trade relations.

The woman from Hechtsheim was a wealthy lady during her lifetime. This is indicated by the rich burial objects such as the silver spoon with the cross and IOHANNIS inscription. The artificially deformed skull of the woman from Münchfeld, which is unusual among Franconians, indicates her foreign origin. Perhaps she was Thuringian.

The burial ground near St. Alban south of the city, which was already documented in Roman times, continued to be used in Frankish times. A large funerary and memorial building testifies to early Christian use.

From 751, the Carolingians assumed the rule of the Frankish Empire. With the expansion of the empire to the north, east and south, the area along the Rhine finally became the centre of power. This is where Charlemagne (r. 768-814) promoted monasteries and bishoprics, built royal palaces, held court meetings and gathered his army for campaigns. Reforms of education, the church, the liturgy, law and writing emanated from Charles and his court of scholars and intellectuals.

During this time, Mainz continued to flourish. Documentation exists showing several stays of Carolingian rulers in Mainz. The city developed into a political and economic centre of the Frankish Empire. With the granting of the permanent dignity of an archbishopric under Charlemagne and the territorial expansions in the east, the ecclesiastical province of Mainz became the largest diocese and the archbishop of Mainz was one of the most powerful men in the empire.

Nevertheless, Mainz once again flourished. The city wall was repaired and now also included the southern settlement area of Selenhofen. The Mainz area was also responsible for reconstructing and securing individual sections of the wall. The lively building activity also included the further decoration of the cathedral as well as richly furnished secular buildings.

Mainz again became a capital city in the empire with important imperial assemblies and imperial congresses. The highlight was the Mainz Court Festival on the Maaraue at Whitsun 1184. It is considered to be the largest, most glamorous and most famous court festival of the Middle Ages, attracting secular and clerical princes from all over the empire and Europe.

From 1138, the Hohenstaufen dynasty ruled over the Holy Roman Empire. Since the previous century, a new power had been emerging in Mainz alongside the archbishop as the city ruler and the king – the citizens as a community that acts independently. Archbishops and kings repeatedly granted them important privileges. On the bronze door of Willigis (r. 975-1011) at Mainz Cathedral, you can still read the privileges from the Archbishop of Mainz, Adalbert I (r. 1111-1137). The citizens of the up-and-coming city were at odds with the archepiscopal city ruler throughout their lives. They want autonomy and self-government, co-determination and independence from the city ruler.

At the end of the Hohenstaufen period, Mainz, Worms and numerous other cities throughout Germany, the princes, counts and lords founded the Rhenish League of Cities to maintain peace and order. For the first time, citizens were allowed to elect their city councillors. The Jewish SchUM communities in Speyer, Worms and Mainz made a decisive contribution to the Rhenish cities flourishing.

Different weapons and elaborately decorated spurs and stirrups indicate wealthy and high-ranking riders. Perhaps they were in the service of Charlemagne. The black-toned jug was an exclusive long-distance commodity. It was used as a drinking jug on the tables of both secular and ecclesiastical grandees.

From 919, the Ottonians ruled the East Frankish-German Empire for around a century. Mainz became increasingly powerful during this time. The archbishops of Mainz were among the ecclesiastical and political leaders of the empire. They held high offices in the royal administration.

Since Charlemagne, the archbishops of Mainz ruled over the largest ecclesiastical province. It stretched from the diocese of Verden in the north, through Halberstadt and Eichstädt in the east, to Constance and Chur in the south. Numerous sovereign stays are documented. Mainz prospered politically and economically.

Caught between royal and archepiscopal rule, the Jewish community contributed to the urban development of Mainz since its beginnings in the 10th century. It helped shape the cityscape and had a far-reaching effect, even far beyond Mainz.

The first Jewish community in Mainz can be traced back to the middle of the 10th century at the latest. Mainz became the "mother community" of Jews in the Rhineland. The community significantly contributed to the city’s flourishing and urban development. Emperors and bishops encouraged Jews to settle by granting them privileges and issuing letters of protection. Periods of peaceful coexistence between Christians and Jews were followed by repeated anti-Jewish pogroms.
A Jewish community has a synagogue, a mikvah (ritual bath) and a cemetery. The Mainz cemetery "auf dem Judensand" is the oldest and largest medieval Jewish cemetery in Europe.

The tombstone of Yehuda son of Schne'or is the oldest surviving dated tombstone north of the Alps. Amram, son of Jonah, was one of the most important scholars of the Jewish community in Mainz. According to the epitaph, he came to Mainz from Jerusalem. He died on the "Day of Wrath," that is, during a persecution of Jews on 31 August 1086.

Their Talmud schools were highly regarded in Europe, with scholars and students coming from far and wide. The joint statutes adopted in 1220 and the architectural forms developed in the three cities for synagogues, mikvahs and women's prayer rooms, as well as the burial culture, had a significant influence on the ritual buildings, culture and identity of Judaism north of the Alps.

Sch → Schin = Schpira = Speyer

U → Waw = Warmaisa = Worms

A Jewish quarter emerged in the 10th and 11th centuries in Mainz. A synagogue was already documented for the time around 1000. Inscriptions on the synagogue tell about the benefactors, their donations, the building activities and prayer rooms. The synagogues have had separate prayer rooms for women since the 13th century.

The Jewish cemeteries are located outside the city. Those buried here have a perpetual right to rest. Since the Middle Ages, an equal proportion of gravestones have been found – unlike in Christian cemeteries – for women and men. The grave inscriptions in Hebrew give the name of the deceased, the name of the father, and the date of death according to the Jewish calendar.
The citizens of Mainz emancipated themselves from their archepiscopal city ruler. The use of a seal manifests their legal community and self-confidence. The oldest Mainz city seal shows the enthroned patron saint of Mainz. Saint Martin praises the city as AVREA MAGONTIA – Golden Mainz, "special daughter of the Roman Church".

[Quote from Otto von Freising.]

"The aforementioned great and mighty city lies on the Rhine and is densely built and populated on the side that touches it, but empty on the other side, has only a few inhabitants there, has only the strong wall with not a few towers that surround it [...], because on the side facing Gaul a moderate hill constricts it, on the other side, looking towards Germania, the Rhine. Therefore, near the Rhine, it is covered with fine churches and secular buildings and lends itself to viticulture and other uses after the mountains."

Bishop Otto of Freising (died 1158), Gesta Friderici I. imperatoris

But Mainz was also of central political importance. The archbishop of Mainz resided here, and kings and emperors stayed here time and again. Outstanding goldsmith works such as the eagle brooch were found here, in a narrow area in the city centre.

Perhaps an empress once wore this jewellery.

To this day, it remains unclear whether the other discoveries in what is known as Mainz gold jewellery were also found in this context. They were misappropriated after being found and ended up in the art trade via Wiesbaden. Today they are located in Berlin.

Willigis was the first archbishop in the empire to mint coins with his portrait. It was also he who crowned Henry II in 1002. Not at the traditional coronation site in Aachen, but in his metropolis Mainz. A panel with a wickerwork motif and remnants of old colour painting testify to the magnificent decoration of the coronation church of the "Old" Cathedral, now St. John's Church. Willigis built a new, imposing cathedral directly to its east. Reconstruction began immediately after it burned down in 1009 on the day of its consecration.

It is unclear where the door was used in Roman times. It may have been for a representative building, the stage theatre or a temple. A 12th-century source describes a "particularly splendid door", later also called "Porta Aurea", Golden Door, belonging to the monastery of St. Alban, which neighbored the site. Speculation as to whether this door is identical to the early Roman door, which may have been reused in the monastery and thus survived the ages, cannot be substantiated.

The Albansberg outside Mainz, with a Merovingian burial ground, probably had a spiritual, perhaps monastic community since the 7th century. Such is indicated by the tombstones of the priest Badegisel and the abbot Pertram.

The newly founded St. Albans Monastery under Charlemagne, with one of the largest church buildings of its time, quickly assumed a prominent position in the bishopric of Mainz and within the empire. It is the burial place of Mainz archbishops, royal and imperial family members, such as Charlemagne's fourth wife, Fastrada, and the site of important imperial and church assemblies.

Mainz was at the peak of its economic importance around 1300. The city on the Rhine maintained extensive trade relations with all regions that were known at that time – economy and trade flourish. The citizens of Mainz also benefitted from this. The representative construction of a department store in the city centre illustrates its self-confidence.

The Archbishop of Mainz was the lord of the city. As one of the most powerful princes of the empire, he helped elect the king or emperor. The archbishop and the citizenry were closely connected. Citizens' concerns were regulated by freely elected councillors under the leadership of two mayors. Of these councillors, 29 were provided by the “houses", i.e. the traditional ruling class, and 29 by the guilds.

Mainz was an impressive sight. The centre behind the city wall along the Rhine was densely built-up. This is where the cathedral, numerous churches and monasteries, as well as also patrician and burgher houses as half-timbered or stone buildings arose. Street names testified to the resident crafts, trades, markets and institutions, such as Fischer- and Heugasse (fish and hay lane), Eisen- and Flachsmarkt (iron and flax market), Unter den Schmieden (under the blacksmith’s) and Unter den Hutmachern (under the hat maker’s) as well as Augustinergasse which is named after its monastery. The Mainz district also included villages outside the city walls, such as Hechtsheim, Gonsenheim and Mombach. They were subject to Mainz’s secular court.

The brisk building activity in Mainz continued in the first decades of the 14th century. This is evidenced, for example, by the new municipal department store built by the citizens of Mainz. But churches and monasteries, as well as the homes of wealthy patrician families, were also magnificently furnished. Sculptures of Madonnas adorned the facades and were supposed to protect the building, and murals decorate the interiors.

After Mainz experienced strong economic growth and a strengthening of the “houses" in the 13th and 14th centuries, growing tensions arose from the 14th century onward. Guilds, patricians and the archbishop were in a bitter dispute. The city lost its leading economic role to Frankfurt and was heavily in debt.

In the middle of the 15th century, the archbishop finally asserted himself against the citizens as city ruler and ensured a renewed upswing of the city. The buildings of wealthy citizens and families were decorated with elaborate architectural sculptures, such as the house Madonnas, typical of Mainz. Art and science were supported and the University of Mainz was founded in 1477. Johannes Gensfleisch, known as Gutenberg, invented printing with movable type, ushering in a new era.

The eight full-figure sandstone reliefs depict the seven electors and the Roman-German king. They are from the exterior of the department store at Brand, completed in 1317 in the centre of Mainz. The seven electors, three ecclesiastical and four secular, headed the empire. They alone elected the king (kur = election). The present set-up corresponds to its order "in all public imperial acts", which was regulated by the Golden Bull as the new basic order of the Empire in 1356. The Archbishop of Mainz, who is standing to the king’s right, played the decisive role in electing the king. He was the last person to cast his vote, and thus the one who decided the election.

From the beginning of the 14th century until its demolition in 1812, the municipal department store stood in a central location in Mainz, known as Brand, not far from the Rhine. Together with other municipal institutions in its vicinity, it formed the secular counterpart to the nearby cathedral district. It was built on behalf of the citizens of Mainz as the largest department store in southwestern Germany. A privilege of King Louis IV from 1317 allowed them to collect a "moderate levy" from the sale of goods in this establishment. It was intended for wholesale and served as a dry, fireproof and theft-proof storage facility. According to a Mainz customs ordinance, merchants passing through were required to lay out their goods for three days, i.e., to "pile them up," and offer them for sale.

From the beginning of the 14th century until its demolition in 1812, the municipal department store stood in a central location in Mainz, known as Brand, not far from the Rhine. Together with other municipal institutions in its vicinity, it formed the secular counterpart to the nearby cathedral district. It was built on behalf of the citizens of Mainz as the largest department store in southwestern Germany. A privilege of King Louis IV from 1317 allowed them to collect a "moderate levy" from the sale of goods in this establishment. It was intended for wholesale and served as a dry, fireproof and theft-proof storage facility. According to a Mainz customs ordinance, merchants passing through were required to lay out their goods for three days, i.e., to "pile them up," and offer them for sale.

Mainz's convenient location makes it a thriving transhipment centre. The goods traded in the department store at Brand are well-known thanks to reports of foreign merchants and the department store regulations of 1437/1444. Thus, there were everyday goods, such as fabrics, cloth, leather, metals, food, paints and colour bases. However, luxury goods, such as North and Baltic Sea fish, exotic spices from grains of paradise to nutmeg, precious silk, pearls and other precious goods were also offered.

Various coins, such as the gold florins, bear witness to this lucrative trade and the wide long-distance relations.

Archbishop Adalbert (r. 1111-1137) granted the citizens of Mainz freedoms in court and taxation. This was the first time that the right to use the civic seal was given. This right symbolizes the emancipation of the citizens from their archepiscopal city lord by representing themselves as their own legal community. As one of the oldest city seals ever, the first Mainz seal shows St. Martin, the patron saint of the city, surrounded by walls and towers. The inscription praises the city as "Aurea Magontia" and as a "special daughter of the Roman Church".

Later, Gothic seals show the unique depiction of St. Martin asleep and dreaming of sharing his coat, as well as, for the first time, the Mainz double wheel, which from then on represented the city's coat of arms.