[1] Theodoric wrote a brief history of the kings of Norway in Latin, Historia de Antiquitate Regum Norwagiensium sometime between 1177 and 1188.
His work, which was dedicated to Archbishop Eystein Erlendsson of Nidaros (1161-1188), remains an important source to the oldest parts of Norway's modern-time history.
In his work, Theodoricus left out the most recent period of Norwegian history.
Theodoric states that he considered it "utterly unfitting to record for posterity the crimes, killings, perjuries, parricides, desecrations of holy places, the contempt for God, the plundering no less of the clergy than of the whole people, the abductions of women and other abominations which it would take long to enumerate"[2] which followed the death of King Sigurðr.
[3] Theodoric's work is one of the Norwegian synoptics, the oldest preserved kings' sagas.