His predecessor Diether III.
In 1462 there was warfare between two rival archbishops, Diether or Dietrich II.
The citizens espoused the cause of Diether, but their city was captured by Adolph; it was then deprived of its privileges and was made subject to the archbishop. Many of the inhabitants were driven into exile, and these carried into other lands a knowledge of the art of printing, which had been invented at Mainz by Johann Gutenberg in 1450.
What the pope actually sought to combat by his dissolution of the Roman Academy 1 Diether von Isenburg (1412-1463), second son of Count Diether of Isenburg-Biidingen; rector of the university of Erfurt, 1434; archbishop of Mainz, 1459.