The chief task of the bishops of the new see was the conversion of the Wends, to which Bishops Volkold (died 992) and Eido (died 1015) devoted themselves with great zeal; but the slow evangelization was yet incomplete when the investiture conflict threatened to arrest it effectively. Saint Benno (1066–1106), bishop when these troubles were most serious, was appointed by Henry IV and appears to have been in complete accord with the emperor until 1076; in that year, although he had taken no part in the Great Saxon Revolt, he was imprisoned by Henry for nine months. Escaping, he joined the Saxon princes, espoused the cause of Pope Gregory VII, and in 1085 took part in the Gregorian Synod of Quedlinburg, for which he was deprived of his office by the emperor, a more imperially disposed bishop being appointed in his place. On the death of Gregory, Benno made peace with Henry, was reappointed to his former see in 1086, and devoted himself entirely to missionary work among the Slavs. Among his successors, Herwig (died 1119) sided with the pope, Godebold with the emperor. In the 13th century the pagan Wends were finally converted to Christianity, chiefly through the efforts of the great Cistercian monasteries, the most important of which were Dobrilugk and Neuzelle. Among the convents of nuns, Heiligenkreuz () at Meissen, Marienthal near Zittau, on the White Elster, and Mühlberg (Marienstern Abbey) deserve mention. In 1365 Pope Urban V appointed the Archbishop of Prague legatus natus, or perpetual representative of the Holy See, for the Dioceses of Meissen, Bamberg and Regensburg (Ratisbon); the opposition of Magdeburg made it impossible to exercise in Meissen the privileges of this office, and Meissen remained, though under protest, subject to the jurisdiction of the Metropolitan of Magdeburg. John's successor, John II of Jenstein (1376-9), who resigned Meissen on his election to the see of Prague, Nicholas I (1379–1392), John III (1393-8), and Thimo of Colditz (1399–1410), were appointed directly from Rome, which set aside the elective rights of the cathedral chapter. Thimo, a Bohemian by birth, neglected the diocese and ruined it financially.