When the insurgents under Duke Otto were joined by the Thuringians, Henry was compelled in 1074 to release Magnus and to make a number of concessions as the price of the peace of Gerstungen; which, however, was short-lived, as the peasants employed in pursuance of its terms in demolishing the forts, desecrated the churches and violated the ducal tombs.
The Thuringians are first mentioned by Vegetius Renatus about A.D.
It remained under the direct rule of the Frankish kings until 634, when Radulf was appointed duke of the Thuringians by King Dagobert I.
About this time the conversion of the Thuringians to Christianity was begun by British missionaries and continued by St Boniface, who founded a bishopric at Erfurt.
During the 1 rth century the Thuringians refused to pay tithes to Siegfried, archbishop of Mainz, and this was probably one reason why they joined the rising of the Saxons against the emperor Henry IV.