The Bulgar calendar was a calendar system used by the Bulgars, a seminomadic people, originally from Central Asia, who from the 2nd century onwards dwelt in the Eurasian steppes north of the Caucasus and around the banks of river Volga. In 681, part of the Bulgars settled in the Balkan peninsula and established Bulgaria.
The main source of information used for reconstruction of the Bulgar calendar is a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Additionally, the same dating system is used in a marginal note in a manuscript by 10th century monk Tudor Doksov and in the Chatalar inscription by the 9th-century Bulgarian ruler Omurtag (r. 814-831), who also provides the Byzantine imperial dating equivalent (the indiction). According to the reconstructed calendar, the Bulgars used a 12-year cyclic calendar similar to the one adopted by Turkic peoples from the Chinese calendar, with names and numbers that are deciphered as in Bulgar language. The reading, along with the "cyclic calendar" interpretation itself, was originally proposed by Finnish Slavist Jooseppi Julius Mikkola in 1913. Later, there have been various modifications and elaborations during the 20th century by scholars such as Géza Fehér, Omeljan Pritsak, Mosko Moskov and other scientists. Peter Dobrev, who supports an "Iranian" fringe theory about the origin of the Bulgars, argues the Turkic names of the animals show that the Turkic peoples had borrowed these words from the Iranian Bulgars.
Reconstructions vary slightly, because some of the names are unattested, and the exact form of a few is debatable. The following list is based on Mosko Moskov's description of the average mainstream interpretation, as well as his own reconstruction, and takes into account the existing disagreements: