Orhon (or Orkhon) inscriptions are the oldest known Turkic writings, which were erected near the Orhon river (between 732-735 AD) in honour of two Kokturk princes Kul and Bilge. They have been carved on two monuments by old Turkic runes (see Old Turkic alphabet), which were deciphered by the Danish philologist Vilhelm Thomsen in 1893. Comparing with monuments left by Tu-jue 突厥 (tu2 jue2) in China, the inscription was the fundamental proof of the equivalence of Gokturks and Tu-jue 突厥 (tu2 jue2) as the alpahbets were equivalent.