The Islamic or Hijri calendar has 354 days in a year, divided into 12 lunar months of either 29 or 30 days (29.5 days is the time taken by the moon to complete a full circle around the earth). This calendar is used in many Islamic countries as the primary way to date events, and by all devout Muslims to track the observance of Islamic holy days. The Hijri calendar is named for the year 622 CE, when the Hijra occurred—the emigration of the Prophet Muhammad and some of his followers from Mecca to Medina to escape their enemies. Islamic years are labeled as AH (from the Latin phrase anno Hegirae, or “in the year of the Hijra”); for example, the Gregorian year 2008 CE corresponds to 1429 AH in the Islamic calendar. The Hijri calendar first came into use in 638 CE, when it was introduced in Medina by Caliph Umar ibn al-Khattab, a close companion of Muhammad.
Because the lunar year is shorter than the solar year (the time taken by the earth to complete a full circle around the sun), fixed events or celebrations in the Islamic calendar fall 11 days earlier with each successive solar year, taking 33 years to move through the entire cycle of the solar calendar. The calendar used in Arabia prior to the introduction of the Islamic calendar was a luniso- lar calendar that used lunar months, but that occasionally had an additional intercalary month inserted in order to keep the calendar in alignment with the natural seasons arising from the sun’s annual peregrinations. The Qur’an forbids this practice in Surah 9, verses 36-37, which state that God has ordained a fixed number of months (12) each year, and that transposing of additional months is arbitrary and is an act of Unbelief.
The first day of each Hijri year is called Ras as- Sana (“head of the year”), and the names of the 12 months of the year reflect their origins in more ancient systems for marking the solar seasons. The months are Muharram (the sacred month), Safar (the month that is void), Rabi’ al-awwal (the first spring), Rabi’ al-than (the second spring), Jumada al-awwa (the first month of dryness), Jumada al- thani (the second month of dryness), Rajab (the revered month), Sha’aban (the month of division), Ramadan (the month of great heat), Shawwal (the month of hunting), Dhu al-Qi’dah (the month of rest), and Dhu-al-Hijjah (the month of pilgrimage). Four of these months (Dhu al-Qi’dah, Dhu-al-Hijjah, Muharram, and Rajab) are considered sacred, because fighting was traditionally forbidden during them, and sins and good deeds carried more weight at these times than during the rest of the year. Ramadan is the month when Muslims focus on the moral and spiritual elements of life, fulfilling the fourth pillar of Islam (sawm or fasting) by practicing abstinence and fasting each day from sunrise until sunset, and by engaging in self-reflection and acts of kindness and generosity. During the month of Dhu-al-Hijjah, devout Muslims fulfill the fifth pillar of Islamic religious obligation (hajj) by making a pilgrimage to Mecca in Saudi Arabia. Two major festivals are universally celebrated by all Muslims; these are Id al-Adha (the Festival of Sacrifice), and Id al-Fatir (the Festival of Breaking of the Fast). Id al-Adha occurs on the tenth day of the month of Dhu-al- Hijjah, signaling the official end of the hajj pilgrimage with communal prayer and the sacrifice of animals. Id al-Fatir is celebrated for 3 days at the end of Ramadan; it marks the end of a full month of fasting with acts that honor God’s benevolence, including feasting, gift-giving, visiting friends and family, and helping the poor.
The Islamic weekly calendar is derived from the Jewish Abrahamic tradition, with each day beginning at sunset. The days of the week are called yaum al-ahad (meaning “first day,” and corresponding to Sunday in the Christian calendar), yaum al-ithnayn (second day), yaum ath-thulaathaa’ (third day), yaum al-arbia’aa’ (fourth day), yaum al-khamis (fifth day), yaum-al-jumu’a (gathering day), and yaum as-sabt (Sabbath day). At noon on yaum-al- jumu’a (Friday), Muslims gather at a mosque or masjid for worship.
Islamic months begin at sunset of the day when the hilal or lunar crescent is first visually sighted. Although this method is still followed in India, Pakistan, and Jordan, visual observations can be inaccurate because of atmospheric conditions or because of the differences in the timing of moonrise across international time zones. Arithmetical astronomical calculations are therefore often used instead to set the calendar and to designate important holy days. In Saudi Arabia and most of the Gulf states, however, the Umm al-Qura calendar (based on precise observations of the new crescent moon in Riyadh) is used, causing holy days to be celebrated in that country several days in advance of other Muslim countries. To solve this problem, several prominent Islamic governance councils have since 1419 AH (1998-1999 CE) adopted an updated methodology for calculating the Umm al- Qura calendar that results in a uniform standard for determining Islamic days of observance. Another variant of the Islamic calendar, developed by early Muslim astronomers, is the Fatamid or tabular Islamic calendar, which uses arithmetic rules to set out a predictable 30-year cycle of years that has 19 years of 354 days and 11 leap years of 355 days. This calendar is accurate to within 1 day over a 2,500 year period, and is most often used as a way to date historical events or to convert dates between the Hegira and Gregorian calendars.
See also Astronomical Calendar; Asian Caledars; Islam; Phases of Moon; Religions and Time; Measurements of Time
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