Recorded in some thirty spellings including Dietmar, Dittmar, Diemar, Dettmer, and the diminutives Diem and Thieme, as well as the Patronymics Dittmers and Dettmers, this is a famous German surname. It derives from the pre 7th century personal name Dietmari, which loosely translates as 'Famous race', no doubt a reference to an ancient people of the name. Surnames from personal names form one of the largest groups in the surnames listings, but most are 'Crusader'. That is to say biblical or names of Hebrew origin which were 'borrowed' from the Holy Land following the famous Crusades of the 12th century which were supported by the Knights Templar, who had followings in all the countries of Europe. This name however precedes the Crusades by several centuries and is one of the fairly rare survivors of an earlier time. In England most were lost following the Norman Conquest of 1066, but the germans managed to hold onto theirs. In this case early examples of the surname recording include Ulrich Thimo of Heggbach, Biberach, in the year 1294, and Hainrich Dietmar of Schoenbach in the year 1357.