Dietritch was born at
Nieheim, a small town subject to the
see of Paderborn.
Urban VI here took particular notice of him, made him an abbreviator to the papal chancery, and in 1383 took him with him in his visit to
Charles III of Naples at Naples, an expedition which led to many unpleasant adventures, from which he escaped in 1385 by leaving the Curia. In 1387 he is again found among the abbreviators, and in 1395
Pope Boniface IX appointed him to the
Prince-Bishopric of Verden. His attempt to take possession of the see, however, met with successful opposition. About Easter, 1401, Dietrich was at Erfurt in Germany, where he matriculated at the university. Towards the end of the fourteenth century Johann Peters of Dordrecht had founded at Rome a hospital for German pilgrims, known as Santa Maria dell' Anima, still in existence and united with the German national church at Rome. Dietrich was an energetic promoter of the new foundation, to such an extent that after Peters he deserves to be considered its chief founder. He had to resume his work in the chancery, where his name again appears in 1403. Dietrich had begun to write a chronicle, of which only fragments are extant. His chief importance, however, lies in the part he took in the controversies arising out of the
Great Schism. He accompanied
Gregory XII to
Lucca in May 1408. He took no part in the
Council of Pisa itself, being then in Germany, but he adhered to the pope elected by the council of Pisa (
Alexander V) and to his successor,
Antipope Pope John XXIII resuming his place at the Curia. In view of the increasing confusion in the Church, however, he became one of the most ardent advocates of the appeal to a general council. He was present at the council of Constance as adviser to the German "nation." He died at
Maastricht on 22 March 1418. Dietrich wrote about events in which he either had an intimate personal share or of which he was in an excellent position to obtain accurate information. His most important works are the
Nemus unionis and the
De schismate. Of these the first, compiled at Lucca after the breach with Gregory XII, is a collection of documents which had fallen into his hands during the negotiations for union: papal pronouncements, pamphlets, letters written and received by himself, and the like. The
De schismate libri III, completed on 25 May 1410, describes the history of events since 1376 as he had seen them. It was continued in the
Historia de vita Johannis XXIII. The abundance of its materials makes this work one of the most important authorities for the last stages of the schism. His judgments, however, concerning persons and facts must be taken with caution, Dietrich being strongly partisan. ==Works==