Esegel
Esegels (aka "Izgil" (), "Äsägel", "Askel", "Askil", "Ishkil", "Izgil") were a dynastic tribe, of Turkic linguistic affiliation, in the Middle Ages who joined and would be assimilated into the Volga Bulgars. Numerous records about Esegels in the sources in many languages, in connection with many historical subjects, and across the span of the Eurasian steppes left numerous variations of their name. M. Räsänen suggested Uralo-Altai etymology of this word: "Es-kil", "Es-gil" "Old city", Gumilyov initially linked the Izgils to the "Sijie" (思结) of the Toquz Oghuz; only to later re-identify Izgils with "Xijie" (奚結), another Tiele  tribe. However, Zuev (2002) distinguished Izgil (> Ch. *"a-siək-kiet" 阿悉結 > "Axijie", a Western Tujue tribe according to Chinese sources) from Igil (> Ch. *"ɣiei-kiet" 奚結 > "Xijie", a Tiele tribe) though Zuev controversially links the Igils 奚結 to the Bulgarian clan Uokil and the Indo-European-speaking "Augaloi" in Transoxania. Róna-Tas proposes an Iranian origin: Western Old Turkic "Askil", "Äsägäl" < "äθägäl" < "haθyaka arya" "the very aliens" (cf. Ossetian "æcægælon" < "æcægæ" + "ælon"). However, Tatár (2012) disagrees that Ossetian "æcægælon" was cognate with "Äskäl", as the expected Hungarian cognate to Ossetian would have  been **"Æčgæl" (Hg. **"Ecsgel"), not "székely", the Székely people's endonym which, in Tatár's opinion, might have developed from "Äskil" with these sound-changes: loss of first vowel before or after another vowel's appearance between /s/ & /k/, not in Hungarian but in a foreign source language. Tatár reconstructs *"Äskil" as the Western Turkic tribe's endonym, containing Turkic plural and generalizational suffix "-GIl" and Iranian tribal name "As"; she proposes that the As had been originally part of Iranian-speaking Massagetae and joined the Alans in the 1st century AD, yet one group later split from the Iranian -speaking As community, became allies or subjects of the Turks and subsequently Turkicized as Äskils, only to later become enemies of the Second Turkic Khaganate. Tatár also remarks that if "székely" had developed from "æcægæl" (even in a Turkic source language and not Hungarian), "the Volga Bulgarian Äskils and the Székelys must be of different origin because "æcægæl" is not the source of Askil." Zuev proposes connections with the "Āxījiē" of the Nushibi half of the Ten Arrows tribal confederation of the Western Turkic Khaganate, and the Xionite personal name "Askil/Askel", as mentioned in the "Chronography" of Theophanes the  Confessor (760–818): ""the same month (July 563) ambassadors of Askil/Askel, the king of Hermihions (Greek Ερμηχιονιονων; Lat. Ermechionorum), a tribe living among barbarians near the ocean, came to Constantinople"". Zuev (2004) summarized scholarly opinions on the link between Izgils and Turkic-speaking tribes mentioned by sources in Chinese: A Chinese annalistic account in New Book of Tang about the Western Turkic Khaganate in 651 AD listed five west tribes collectively as Nushibi (弩失畢) and noted that "Kül-Irkin" (闕俟斤 Què-sìjīn), the leader of first tribe, Āxījiē (阿悉結), (whom Zuev identifies as Esegels) "was most prosperous and strong, the  number of his soldiers reached several tens of thousands"". Arab ambassador Ibn Fadlan, who visited Itil ("Volga") banks in the 921–922, mentioned in his journal the Bulgarian tribe "Askel", besides the Bulgars proper, the Suvars (Savan), the Bersula, and the Barandzhar. Persian ethnographer Ahmad ibn Rustah listed three branches of the Volga Bulghars: "the first branch was called Bersula, the second Esegel, and the third Bulgar". Among other writers who mentioned Esegels, the Persian “Geography“ of 982 named "Ishkils" as one of three Bulgarian tribes, who were constantly conflicting among themselves. Gardizi, the author of the composition "Zain al-ahbar  (mid-11th century), wrote: "Between possessions of Bulgars and possessions of Eskels, who also belong to Bulgars, is a Magyar area. These Magyars are also a Türkic tribe". Constantine Porphyrogenitus wrote that endoethnonym of the Magyar Türks" was "Savartoiaskaloi", i.e. "Savart" (Suvar/Sabir) and "Eskel". Zuev summarized that "It is held that Eskels (Esegels) merged with Hungarians (Magyars). Zuev proposes that the ethnographic group "Székely" (also known as Szekler) are Esegels' descendants." However, Róna-Tas rejected identification of Esegels with Székely, as well as the link between the names Esegels and Chigils, on historical and phonological grounds.