Burtas (Russian: Буртасы, Chuvash: Пăртассем, Tatar Cyrillic: Бортаслар, Latin: Bortaslar) were a tribe of uncertain ethnolinguistic affiliation inhabiting the steppe region north of the Caspian Sea in medieval times (modern Penza Oblast, Ulyanovsk Oblast and Saratov Oblast of the Russian Federation). They were subject to the Khazars.
The Burtas are generally believed to be a Uralic tribal confederacy (probably later assimilated to Turkic language), the ancestors of the modern Moksha people as well as some groups (such as Mishars) of Volga Tatars and Chuvash.
Recently, some scholars have challenged the conventional theory, suggesting that the Burtas were actually Alans or another Iranian ethnolinguistic group.
(Tatar) "Бортаслар". Tatar Encyclopedia. Kazan: Tatarstan Republic Academy of Sciences Institution of the Tatar Encyclopaedia. 2002.