DUDO or DUDON (fl. c. I000), Norman historian, was dean of St. Quentin, where he was born about 965. Sent in 986 by Albert I. count of Vermandois, on an errand to Richard I., duke of Normandy, he spent some years in that country. During a second stay in Normandy Dudo wrote his history of the Nor mans, a task which Duke Richard I. had urged him to undertake. Very little else is known about his life, except that he died before 1043. Written between 1015 and 1030, his Historia Norman norum, or Libri III. de moribus et actis primorum Normanniae ducum, was dedicated to Adalberon, bishop of Laon. Dudo ap pears to have obtained his information from oral tradition, much of it being supplied by Raoul, count of Ivry, a half-brother of Duke Richard I. Consequently the Historia partakes of the nature of a romance; nevertheless, J. Lair and J. Steenstrup, while admitting the existence of a legendary element, regard the book as of considerable value for the history of the Normans. The Historia, which is written alternately in prose and in verse of several metres, is divided into four parts, and deals with the history of the Normans from 852 to the death of Duke Richard I. in 996. It was largely used by William of Jumigiges, Wace, Robert of Torigni, William of Poitiers and Hugh of Fleury in compiling their chronicles, and was first published by A. Duchesne in his Historiae Normannorum scriptores antiqui, at Paris in 1619. An other edition is in the Patrologia Latina, tome cxli. of J. P. Migne (Paris, 1844), but the best is perhaps the one edited by J. Lair (Caen, 1865).