Caesarius a German theologian, lived in the early part of the 13th century. He was of the noble family of Milendunk, in the country of Neussef. He was priest of the convent of Prum, belonging to the Benedictine order. After four years he resigned his position and withdrew to the convent of Heslerbach, of the order of the Cistercians. Here he wrote, in 1222, Explicatio Rerum et Verborum, which is found in his Registrum Bonorum Ecclesice Prumiensis. See Hoefer, Nouv. Biog. Generale, s.v.