The Hijri Date, also known as the Islamic calendar date, is based on the lunar cycle. It consists of 12 months, each month having either 29 or 30 days, making a total of about 354 or 355 days in a year. The calendar begins with the month of Muharram and is used primarily by Muslims around the world to determine the dates of religious events and observances. The Hijri calendar was established in 622 CE, the year of the Hijra, when the Prophet Muhammad migrated from Mecca to Medina. This migration marks the beginning of the Islamic era. The Hijri Date is important for scheduling Islamic holidays, such as Eid al-Fitr and Eid al-Adha, which are celebrated on specific days of the lunar calendar.