Archchancellor in the context of Mainz Cathedral

The Electorate of Mainz (German: Kurfürstentum Mainz [ˈkuːɐ̯ˌfʏʁstn̩tuːm ˈmaɪnts] or Kurmainz [kuːɐ̯ˈmaɪnts] ; Latin: Electoratus Moguntinus), previously known in English as Mentz and by its French name Mayence, was one of the most prestigious and influential states of the Holy Roman Empire. In the hierarchy of the Catholic Church, the Archbishop-Elector of Mainz was also the Primate of Germany (primas Germaniae), a purely honorary dignity that was unsuccessfully claimed from time to time by other archbishops. There were only two other ecclesiastical Prince-electors in the Empire: the Electorate of Cologne and the Electorate of Trier.

The Archbishop-Elector of Mainz was also archchancellor of Germany (one of the three component titular kingdoms of the Holy Roman Empire, the other two being Italy and Burgundy) and, as such, ranked first among all ecclesiastical and secular princes of the Empire, and was second only to the Emperor. His political role, particularly as an intermediary between the Estates of the Empire and the Emperor, was considerable.

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.

Baldwin of Luxembourg (c. 1285 – 21 January 1354) was the archbishop and elector of Trier and archchancellor of Burgundy from 1307 to his death. From 1328 to 1336, he was the administrator of the archdiocese of Mainz and from 1331 to 1337 (with interruptions) of the dioceses of Worms and Speyer. He was one of the most prominent German prelates and statesmen of his age, and the most effective ruler of Trier during the late Middle Ages.