The Cappadocian calendar was a solar calendar that was derived from the Persian Zoroastrian calendar. It is named after the historic region Cappadocia in present-day Turkey, where it was used. The calendar, which had 12 months of 30 days each and five epagomenal days, originated between 550 and 330 BC, when Cappadocia was part of the Persian Achaemenid Empire. The Cappadocian calendar was identical to the Zoroastrian calendar; this can be seen in its structure, in the Avestan names and in the order of the months. The Cappadocian calendar reflects the Iranian cultural influence in the region. Extant evidence of the calendar dates back to Late Antiquity through the accounts of Greek astronomers, by which time it had already been adapted to the Julian calendar.