Timekeeping measurement of the Ancient Turks had been affected by the influence of the Steppe culture by nature. The ancient Turkish calendar was based on the principle of "12-year" periods and each of these periods was called with the name of an animal. The names of the years were as follows: . 1. year sıçkan, (mouse), 2. ud (cattle-ox), 3. Leopard, 4. tabışkan (rabbit), 5. Lu (dragon), 6. Snake, 7. Yunt (horse), 8. koy (sheep), 9. biçin (monkey), 10. takagu (chicken), 11. dog, 12. tonguz (pig). There were 12 months within a year. The names of these months were called as birinç (birinci= first) month, ikinç (second), üçünc (third), etc. A day was considered as divided into 12 sections and each section was called as "çağ" (era). A year was composed of 365 days and nearly 5 hours. The offset of the day was the midnight. The New Year would coincide with the months of January-February. This Turkish Calendar with 12 Animals was actually based on lunar year. However, it has been observed that it was turned into the solar year system in the period of the Gokturk State.
The origin of this calendar must have been very deeply rooted. This calendar that was also used as the periods of 60 years that were five folds of the period of 12 years were used among the Gokturk and Uighur people and the Western Turks (Bulgarians) and absolutely by the Huns. It seems that it was a very widespread system in respect of both time and geography. The inscriptions written in the Gokturk language, the Uighur books and legal documents, the Bulgarian inscriptions and the "list of the Bulgarian khans", and even some of the events in Manas epic were dated on the basis of this calendar. This ancient Turkish calendar was cited under the name of "Tarih-i Türkî" (Turkish History) or "Sal-i Türkan" in the 14th and 15th centuries within the Islamic resources.