Tervel of Bulgaria

Tervel, also called Tarvel, Terval, or Terbelis in Byzantine sources, was the ruler of Bulgaria during the First Bulgarian Empire at the beginning of the 8th century. In 705 Emperor Justinian II named him caesar, the first foreigner to receive this title. He was raised a pagan like his grandfather Khan Kubrat, but was later possibly baptised by the Byzantine clergy. Tervel played an important role in defeating the Arabs during the siege of Constantinople in 717–718. The Nominalia of the Bulgarian khans states that Tervel belonged to the Dulo clan and reigned for 21 years. The testimony of the source and some later traditions allow identifying Tervel as the son of Asparukh.