Karl Theodor von Dalberg in the context of "Prince-Primate"

The Elector of Mainz was one of the seven Prince-electors of the Holy Roman Empire. As both the Archbishop of Mainz and the ruling prince of the Electorate of Mainz, the Elector of Mainz held a powerful position during the Middle Ages. The Archbishop-Elector was president of the electoral college, archchancellor of the empire, and the Primate of Germany as the papal legate north of the Alps, until the dissolution of the empire in 1806.

The origin of the title dates back to 747, when the city of Mainz was made the seat of an archbishop, and a succession of able and ambitious prelates made the district under their rule a strong and vigorous state. Among these men were important figures in the history of Germany such as Hatto I, Adalbert of Mainz, Siegfried III, Peter of Aspelt and Albert of Brandenburg. There were several violent contests between rivals for the archbishopric, and their power struggles occasionally moved the citizens of Mainz to revolt. The lands of the elector lay around the city of Mainz on both banks of the Rhine; their area reached 3200 sq. miles by the end of the Empire. The last elector was Karl Theodor von Dalberg, who lost his temporal power when the archbishopric was secularized in 1803.