Vikram Samvat is a historical calendar system used primarily in India and Nepal. It is believed to have been established by King Vikramaditya in 57 BCE. The calendar is a lunisolar system, meaning it is based on both the moon's phases and the sun's position. It typically runs about 57 years ahead of the Gregorian calendar, which is the most widely used calendar today. The Vikram Samvat year begins in the month of Chaitra, usually falling in March or April of the Gregorian calendar. Each month consists of either 29 or 30 days, and the calendar includes various festivals and cultural events significant to the regions that observe it.