Eid ul-Fitr is the earlier of the two official holidays celebrated within Islam (the other being Eid al-Adha). The religious holiday is celebrated by Muslims worldwide because it marks the end of the month-long dawn-to-sunset fasting of Ramadan. It falls on the first day of Shawwal in the Islamic calendar; this does not always fall on the same Gregorian day, as the start of any lunar Hijri month varies based on when the new moon is sighted by local religious authorities. The holiday is known under various other names in different languages and countries around the world. The day is also called Lesser Eid, or simply Eid.