animal cycle, similar to the one adopted by Turkic and Mongolian peoples from the Chinese, with animal names and numbers deciphered as Turkic. Tengri (in Bulgar Tangra/Tengre) was their supreme god. Bulgar inscriptions were written mostly in Greek or Cyrillic characters, most commonly in Greek or Graeco-Bulgar, sometimes with Slavic terms, thus allowing scholars to identify some of the Bulgar glosses. Several Bulgar inscriptions were found in Northeastern Bulgaria and parts of Romania, written in runes similar to the Old Turkic alphabet; they apparently have a sacral meaning. Altheim argued that the runes were brought into Europe from Central Asia by the Huns, and were an adapted version of the old Sogdian alphabet in the Hunnic/Oghur Turkic language. The custom of stone engravings are considered to have Sasanian, Turkic and Roman parallels. The Madara Rider resembles work of the Sasanian rock relief tradition, but its actual masonry tradition and cultural source is unknown. The Danubian Bulgars were unable to alter the predominantly Slavic character of Bulgaria, seen in the toponymy and names of the capitals Pliska and Preslav. They preserved their own native language and customs for about 200 years, but a bilingual period was recorded since the 9th century. Golden argued that Bulgar Turkic almost disappeared with the transition to Christianity and Slavicisation in the middle of the 9th century. When the ruling class abandoned its native language and adopted Slavic, according to Jean W. Sedlar, it was so complete that no trace of Turkic speech patterns remained in Old Slavic texts. The Bulgarian Christian Church used Slavic dialect from Macedonia. Among Bulgarian academics, notably Petar Dobrev, a hypothesis linking the Bulgar language to the Iranian languages (Pamir) has been popular since the 1990s.Милчева, Христина. Българите са с древно-ирански произход. Научна конференция "Средновековна Рус, Волжка България и северното Черноморие в контекста на руските източни връзки", Казан, Русия, 15.10.2007 Most proponents still assume an intermediate stance, proposing certain signs of Iranian influence on a Turkic substrate.Бешевлиев, Веселин. Ирански елементи у първобългарите. Античное Общество, Труды Конференции по изучению проблем античности, стр. 237–247, Издательство "Наука", Москва 1967, АН СССР, Отделение Истории. The names Asparukh and Bezmer from the Nominalia list, for example, were established as being of Iranian origin. Other Bulgarian scholars actively oppose the "Iranian hypothesis".Надпис № 21 от българското златно съкровище "Наги Сент-Миклош", студия от проф. д-р Иван Калчев Добрев от Сборник с материали от Научна конференция на ВА "Г.