- This is about the historical calendar era. For the "Saka calendar" of 1957, see Indian national calendar.
The Saka era is ostensibly the date of accession of the Kushan emperor Kanishka (whose reign is however dated some 50 years later in modern literature). This also need verification. Satavahana's are South Indian Dynasty whose era precedes Kushans. Most of Buddhism spread to south east Asia , similarities in script , same calendar usage in south east Asia indicates the calendar started with Satavahana's.
Some of the early use of the calendar are, the "Western Satraps" of the Kushans, the Saka (Indo-Scythian) rulers of Ujjain, from the reign of Rudrasimha I (178–197) recorded the date of minting of their coins in the Saka era, usually written on the obverse behind the king's head in Brahmi numerals. This is a rather uncommon case in Indian numismatics. Some, such as the numismat R.C. Senior considered that these dates might correspond to the Azes era instead. Use of the calendar era survived into the Gupta period and became part of Hindu tradition following the decline of Buddhism in India. It was in widespread use by the 6th to 7th centuries, e.g. in the works of Varāhamihira and Brahmagupta, and by the 7th century also appears in epigraphy in Hindu Southeast Asia.
The calendar era remained in use in India and Southeast Asia throughout the medieval period, the main alternative era in traditional Hindu timekeeping being the Vikram Samvat era (56 BC). It was used by Javanese courts until 1633, when it was replaced by Anno Javanico, a hybrid Javanese-Islamic system. It was adopted as the era of the Indian national calendar (also known as "Saka calendar") in 1957. The Saka era also remains in is also use in Java and Bali, Indonesia.
The Saka era is the vernal equinox of the year AD 78. The year of the modern Saka Calendar is tied to the Gregorian date of 22 March every year, except in Gregorian leap years when it starts on 23 March.
- Rapson, "A Catalogue of Indian coins in the British Museum. Andhras etc." p. CCVIII
- Ricklefs (1993), pages 5 and 46.