伊斯兰历, also known as the Hijri calendar, is a lunar calendar used by Muslims around the world. It consists of 12 months, totaling 354 or 355 days in a year. The months are based on the phases of the moon, making it about 10 to 12 days shorter than the solar calendar used in most of the world. The first month of the 伊斯兰历 is Muharram, and the calendar is significant for marking important Islamic events, such as Ramadan and Eid al-Fitr. The year is denoted as AH (Anno Hegirae), which refers to the migration of the Prophet Muhammad from Mecca to Medina.