"thirty" in Proto-Bulgar; otuz in Common Turkic) – as 'Oğur (Oghur) tribes, with the ethnonym Bulgar as a "spreading" adjective. Golden considered the origin of the Kutrigurs and Utigurs to be obscure and their relationship to the Onogurs and Bulgars – who lived in similar areas at the same time – as unclear. He noted, however, an implication that the Kutrigurs and Utigurs were related to the Šarağur (šara oğur, shara oghur; "white oğhurs"), and that according to Procopius these were Hunnish tribal unions, of partly Cimmerian descent. Karatay considered the Kutrigurs and Utigurs to be two related, ancestral people, and prominent tribes in the later Bulgar union, but different from the Bulgars. Among many other theories regarding the etymology of Bulgar, the following have also had limited support. an Eastern Germanic root meaning "combative" (i.e. cognate with the Latin pugnax), according to D. Detschev; the Latin burgaroi – a Roman term mercenaries stationed in burgi ("forts") on the limes (G. A. Keramopulos); a reconstructed but unattested early Turkic term meaning "five oğhur", such as *bel-gur or *bil-gur (Zeki Velidi Togan). History Turkic migration The origin of the early Bulgars is still unclear. Their homeland is believed to be situated in Kazakhstan and the North Caucasian steppes. Interaction with the Hunnic tribes, causing the migration, may have occurred there, but the Pontic–Caspian steppe seems a more likely location. The first clear mention and evidence of the Bulgars was in 480, when they served as the allies of the Byzantine Emperor Zeno (474–491) against the Ostrogoths. Anachronistic references about them can also be found in the 7th-century geography work Ashkharatsuyts by Anania Shirakatsi, where the Kup'i Bulgar, Duč'i Bulkar, Olxontor Błkar and immigrant Č'dar Bulkar tribes are mentioned as being in the North Caucasian-Kuban steppes. An obscure reference to Ziezi ex quo Vulgares, with Ziezi being an offspring of Biblical Shem, is in the Chronography of 354. According to D. Dimitrov, the 5th-century History of Armenia by Movses Khorenatsi speaks about two migrations of the Bulgars, from Caucasus to Armenia. The first migration is mentioned in the association with the campaign of Armenian ruler Valarshak (probably Varazdat) to the lands "named Basen by the ancients... and which were afterwards populated by immigrants of the vh' ndur Bulgar Vund, after whose name they (the lands) were named Vanand". The second migration took place during the time of the ruler Arshak III, when