Vikram Samvat is a historical Hindu and luni-solar calendar, named after the legendary king Vikramaditya and introduced in 57 BCE. It is the official calendar of Nepal and is used in parts of India to determine festival dates, including Diwali and Holi. The calendar is based on both the lunar cycle and the solar cycle, and typically runs about 56 to 57 years ahead of the Gregorian calendar. Name and origin: It is named after King Vikramaditya to commemorate his triumph over the Sakas and is also known as the Vikrami calendar. Calendar type: It is a luni-solar calendar, meaning it follows both the phases of the moon and the movement of the sun.