Charles was the youngest of the three sons of Louis the German, first King of East Francia, and Hemma from the House of Welf. An incident of demonic possession is recorded in his youth, in which he was said to have been foaming at the mouth before he was taken to the altar of the church. This greatly affected him and his father. He was described as: "… a very Christian prince, fearing God, with all his heart keeping His commandments, very devoutly obeying the orders of the Church, generous in alms-giving, practising unceasingly prayer and song, always intent upon celebrating the praises of God."