In the early Middle Ages, Mainz was a centre for the Christianisation of the German and Slavic peoples.
The first archbishop in Mainz, Boniface, was killed in 754 while trying to convert the Frisians to Christianity and is buried in Fulda.
Boniface held a personal title of archbishop; Mainz became a regular archbishopric see in 781, when Boniface's successor Lullus was granted the pallium by Pope Adrian I. Harald Klak, king of Jutland, his family and followers, were baptized at Mainz in 826, in the abbey of St. Alban's.
 Other early archbishops of Mainz include Rabanus Maurus, the scholar and author, and Willigis (975–1011), who began construction on the current building of the Mainz Cathedral and founded the monastery of St. Stephan.

From the time of Willigis until the end of the Holy Roman Empire in 1806, the Archbishops of Mainz were archchancellors of the Empire and the most important of the seven Electors of the German emperor.
Besides Rome, the diocese of Mainz today is the only diocese in the world with an episcopal see that is called a Holy See (sancta sedes).
The Archbishops of Mainz traditionally were primas germaniae, the substitutes of the Pope north of the Alps.

In 1244, Archbishop Siegfried III granted Mainz a city charter, which included the right of the citizens to establish and elect a city council.
The city saw a feud between two archbishops in 1461, namely Diether von Isenburg, who was elected Archbishop by the cathedral chapter and supported by the citizens, and Adolf II von Nassau, who had been named archbishop for Mainz by the pope.
In 1462, the Archbishop Adolf raided the city of Mainz, plundering and killing 400 inhabitants.
At a tribunal, those who had survived lost all their property, which was then divided between those who promised to follow Adolf.
Those who would not promise to follow Adolf (amongst them Johannes Gutenberg) were driven out of the town or thrown into prison.
The new archbishop revoked the city charter of Mainz and put the city under his direct rule.
Ironically, after the death of Adolf II his successor was again Diether von Isenburg, now legally elected by the chapter and named by the Pope.
In the early Middle Ages, Mainz was a centre for the Christianisation of the German and Slavic peoples. The first archbishop in Mainz, Boniface, was killed in 754 while trying to convert the Frisians to Christianity and is buried in Fulda. Boniface held a personal title of archbishop; Mainz became a regular archbishopric see in 781, when Boniface's successor Lullus was granted the pallium by Pope Adrian I. Harald Klak, king of Jutland, his family and followers, were baptized at Mainz in 826, in the abbey of St. Alban's.  Other early archbishops of Mainz include Rabanus Maurus, the scholar and author, and Willigis (975–1011), who began construction on the current building of the Mainz Cathedral and founded the monastery of St. Stephan.
From the time of Willigis until the end of the Holy Roman Empire in 1806, the Archbishops of Mainz were archchancellors of the Empire and the most important of the seven Electors of the German emperor. Besides Rome, the diocese of Mainz today is the only diocese in the world with an episcopal see that is called a Holy See (sancta sedes). The Archbishops of Mainz traditionally were primas germaniae, the substitutes of the Pope north of the Alps.
In 1244, Archbishop Siegfried III granted Mainz a city charter, which included the right of the citizens to establish and elect a city council. The city saw a feud between two archbishops in 1461, namely Diether von Isenburg, who was elected Archbishop by the cathedral chapter and supported by the citizens, and Adolf II von Nassau, who had been named archbishop for Mainz by the pope. In 1462, the Archbishop Adolf raided the city of Mainz, plundering and killing 400 inhabitants. At a tribunal, those who had survived lost all their property, which was then divided between those who promised to follow Adolf. Those who would not promise to follow Adolf (amongst them Johannes Gutenberg) were driven out of the town or thrown into prison. The new archbishop revoked the city charter of Mainz and put the city under his direct rule. Ironically, after the death of Adolf II his successor was again Diether von Isenburg, now legally elected by the chapter and named by the Pope.
Mainz