Thietmar (also Dietmar or Dithmar; 25 July 975 – 1 December 1018), Prince-Bishop of Merseburg from 1009 until his death in 1018, was an important chronicler recording the reigns of German kings and Holy Roman Emperors of the Ottonian (Saxon) dynasty. Two of Thietmar's great-grandfathers, both referred to as Liuthar, were the Saxon nobles Lothar II, Count of Stade, and Lothar I, Count of Walbeck. They were both killed fighting the Slavs at the Battle of Lenzen. Source: Wikipedia (en)