Abbot of the Benedictine monastery, near Trier, afterwards a Cistercian monk at Heisterbach near Bonn, born of the noble family of Milendonk, and lived in the latter half of the twelfth and in the first half of the thirteenth century. At the beginning of the thirteenth century he entered the monastery of Prüm, where in 1212 he was elected abbot, to succeed Gerard of Vianden. Prüm was then one of the richest monasteries in Europe, with large estates scattered over Germany, France, and the Netherlands. Many of the monks were noblemen who had entered the monastery in order to live a life of comfort. Their example began to undermine the monastic simplicity and discipline, without which no monastery can prosper for any length of time. After ruling five years Caesarius, probably because he desired to lead a more perfect life than he could as abbot of a rich and undisciplined monastery, resigned his abbatial dignity and became a hungle monk at the flourishing Cistercian monastery of Heisterbach. Upon the request of Abbot Kuno of Prüm he wrote, in 1222, a commentary on the "Registrum Bonorum" or "Register of the Estates of Prüm", which had been drawn up by an unknown monk in 893. This commentary has become an important source for the history of law and civilization during the thirteenth century. The "Register", together with the commentary of Caesarius, was published by Leibniz in his "Collectanea Etymologica" (Hanover, 1717), II, 409 sqq., and by Hontheim in his "Historia Trevirensis" (Augsburg, 1750), I, 661 sqq. The latest and best edition, made from the original manuscript of Caesarius, which is preserved in the royal archives at Berlin, was brought out by Heinrich Beyer in "Urkundenbuch zur Geschichte der mittelrheinischen Territorien" (Coblenz, 1860), I, 142-201. Schönbach in "Sitzungsberichte der k. Akademie der Wissenschaften" (Vienna, 1902) after careful researches ascribes to Caesarius of Milendonk the important historical work "De Abbatibus Prumiensibus", which heretofore was believed to have been written by Caesarius of Heisterbach.
ZEIGELBAUER, Hist. Litt. O.S.B. (Augsburg and Würzburg, 1754), III, 170; LAMPRECHT, Deutsches Wirtschaftsleben im Mittelalter (Leipzig, 1886), II, 60.
MICHAEL OTT