right|thumb|200px|[[Tamgha of the Dulo clan.]]
The Dulo clan was a ruling dynasty of the Bulgars, who were of Turkic origin. Particularly, it is said that the Dulo descended from the rulers of Old Great Bulgaria. This state was a centralized monarchy from its inception, unlike previous Hunno-Turkic political entities, which were tribal confederations.
The royal family and rulers of Old Great Bulgaria (632–668) and the first half of the First Bulgarian Empire (681–1018), in their prince lists (Nominalia of the Bulgarian khans) claimed through descent from Attila through Irnik, possibly Attila's attested son Ernak. At the head of the clan was the Khan, who reigned as the head of state, military leader, and probably high priest of the Bulgar god, Tangra. According to him the Nominalia shows that the clan memory and genealogy important to Central Asian peoples was likewise significant to the Bulgars, as well the cosmological understanding of the history, as the Avitohol and Irnik were mentioned in the category of the creator and founder, the mythological divine ancestor-creator represented in the reincarnation of the cultural hero within time cycles. Jean W. Sedlar considered the Attila connection justly doubtful, and argued the possibility of a steppe dynasty which produced Hunnic rulers like Attila may have also produced rulers for the Bulgars.
The second listed ruler is Irnik, who lived 150 years and also descended from the Dulo clan. It is generally considered that in the Nominalia under Irnik was considered the third son of Attila, Ernak. Historians usually interpreted the testimony as evidence of a massacre of the previous dynasty (the Dulo clan), and the rise of a new leader with no connection to the previous regime.
Origin
The exact origin is obscure. This proposition was suggested by Mikhail Artamonov, and was prompted by Lev Gumilev (1967), implying there may be made an association of the Dulo clan with the five Duolu (or To-lu) tribes of the Western Turks. B. Zhivkov emphasized that Duolu and Nushibi were tribal confederations, and not ruling dynasties. Accurately or not, it still points to the rivalry between the Bulgars, led by Kubrat from the Dulo clan, and the Khazars, led by the Ashina clan. Peter B. Golden surmises that the Xiongnu tribal surname 獨孤 Dugu (< d'uk-kuo) or 屠各 Tuge (< d'o-klâk) possibly reflects underlying Turkic *Tuğqu or *Tuğlağ "tribe of the tuğ?" yet still considers the Turkic association as speculative. MacDermott considered that the Bulgarian expression preserved to this day "he kills the dog", in the meaning "he gives the orders", is a relic of the time when the Dulo Khan sacrificed a dog to the deity Tangra in the name of the whole community. As such the proto-Bulgar language (of the group which established the state of Bulgaria), was claimed to be of Iranian language although it is generally accepted it was Turkic of Oghuric branch and related to modern Chuvash. Even so, all hypotheses P. B. Golden considers for now as speculative.