Which rulers were honoured by the 8th-century Orhon River inscriptions?

The 8th-century Orhon River inscriptions, which are the oldest extant writings in a Turkic language, were erected to honour two prominent figures of the Turk dynasty:

• Prince Kül (died 731), who was honoured by a monument erected in 732.1
• Emperor Bilge (died 734), his brother, who was honoured by a monument erected in 735.1

These inscriptions, discovered in the Orhon River valley in Mongolia, were deciphered in 1893 by the Danish philologist Vilhelm Thomsen. They provide significant historical accounts of the Turkic people, including their legendary origins, their history of subjugation, and their eventual liberation under Bilge.12