an historian of the 12th century, was a priest at Bosau near Plon. He was a friend of the two bishops of Oldenburg, Vicelin (d. 1154) and Gerold (d. 1163), who did much to Christianize the Sla y s. At Bishop Gerold's instigation Helmold wrote his Chronica Slavorum, a history of the conquest and conversion of the Slavonic countries from the time of Charlemagne. For the life and times of Henry the Lion, duke of Saxony, Helmold's chronicle, as that of a contemporary who had exceptional means for gaining information, is of first-rate importance. The history was continued down to 1209 by Abbot Arnold of Lubeck.
The Chronica were first edited by Siegmund Schorkel (Frankfort a. M., 1556). The best edition is by J. M. Lappenberg in Mon. Germ. hist. scriptores, xxi. (1869). For critical works on the Chronica see A. Potthast, Bibliotheca hist. med. aevi, s. "Helmoldus."