The Javanese calendar is used by the main ethnicities of Java island—that is, the Javanese, Madurese, and Sundanese people—primarily as a cultural icon and identifier, and as a maintained tradition of antiquity. The Javanese calendar is used for cultural, metaphysical, and spiritual purposes.
The current system of the Javanese calendar was inaugurated by Sultan Agung of Mataram in the Gregorian year 1633 CE. Prior to this, the Javanese had used the Hindu calendar(Saka), which begins in 78 CE and uses the solar cycle for calculating time. Sultan Agung's calendar retained the Saka calendar year system of counting, but differs by using the same lunar year measurement system as the Islamic calendar, rather than the solar year. Occasionally, the Javanese calendar is referred to by its Latin name Anno Javanico or AJ (Javanese Year).