era beginning in 57 BCE with Vikramaditya is not found in any source before the 9th century CE; earlier sources call the era "Kṛṭa" (343 and 371 CE), "Kritaa" (404), "the era of the Malava tribe" (424), or simply "Samvat". The earliest known inscription which calls the era "Vikrama" is from 842. This inscription, from the Chauhana ruler Chandamahasena, was found at Dholpur and is dated "Vikrama Samvat 898, Vaishakha Shukla 2, Chanda" (20 April 842). The earliest known inscription which associates the era with a king called Vikramaditya is dated 971, and the earliest literary work connecting the era to Vikramaditya is Subhashita-Ratna-Sandoha (993-994) by the Jain author Amitagati. A number of authors believe that the Vikram Samvat was not started by Vikramaditya, who might be a legendary king or a title adopted by a later king who renamed the era after himself. V. A. Smith and D. R. Bhandarkar believed that Chandragupta II adopted the title of Vikramaditya, and changed the era's name to "Vikrama Samvat". According to Rudolf Hoernlé, the king responsible for this change was Yashodharman. Hoernlé believed that he conquered Kashmir and is the "Harsha Vikramaditya" mentioned in Kalhana's Rajatarangini. Some earlier scholars believed that the Vikram Samvat corresponded to the Azes era of the Indo-Scythian (Śaka) king King Azes. This was disputed by Robert Bracey after the discovery of an inscription of Vijayamitra, which is dated in two eras. The theory was discredited by Falk and Bennett, who place the inception of the Azes era in 47–46 BCE. Popularity The Vikram Samvat has been used by Hindus, Sikhs, and Pashtuns. One of several regional Hindu calendars in use on the Indian subcontinent, it is based on twelve synodic lunar months and 365 solar days. The lunar year begins with the new moon of the month of Chaitra. This day, known as Chaitra Sukhladi, is a restricted (optional) holiday in India. The calendar remains in use by people in Nepal serving as its national calendar and is also symbolically used by Hindus of north, west and central India. In south India and portions of east and west India (such as Assam, West Bengal and Gujarat), the Indian national calendar is widely used. With the arrival of Islamic rule, the Hijri calendar became the official calendar of sultanates and the Mughal Empire. During British colonial rule of the Indian subcontinent, the Gregorian calendar was adopted and