ADOLF I, archbishop of MAINZ. — Count of Nassau, great-nephew of King Adolf of Nassau, b. ca. 1353, d. 6 Feb. 1390.
He was proposed by his uncle Gerlach, archbishop of Mainz, to the Chapter as coadjutor with right of succession, which however he did not obtain. Instead, he was appointed bishop of Speyer in 1371. Two years later, he was called by the majority of the Mainz Chapter to occupy the see, but could obtain it only after a struggle against Louis of Thuringia, hitherto bishop of Bamberg, whom Pope Gregory XI, at the request of Emperor Charles IV, had designated by bull of 23 Apr. 1374 as administrator of Mainz. In 1381, Pope Urban VI transferred Louis to Magdeburg and confirmed A. as archbishop of Mainz. On 4 Feb. of the same year he was also recognized by the assembly of German princes at Nuremberg as archbishop-elect and archchancellor. He took an active part in the general politics of the Reich. His contemporaries extolled his prudence and valor. He was more a statesman than a churchman. He showed himself a friend of learning by founding the University of Erfurt in 1389, which, with the privileges granted by Pope Urban VI, was inaugurated in 1392, when A. was already dead.