Please explain how the Islamic Calendar came into existence. What did the earlier Muslims follow? How were the months named, and what is the significance of each name?

ISLAMIC CALENDAR - HISTORY AND MOTIVATION%0D%0A%0D%0AThe Islamic Calendar, which is based purely on lunar cycles, was first%0D%0Aintroduced in 638 CE by the companions of the Prophet, sallallahu alayhi%0D%0Awasallam, and the second Khalifah, Umar ibnul Khattab (592-644 CE).%0D%0A%0D%0AHe did it in an attempt to rationalize the various, at times conflicting,%0D%0Adating systems used during his time. Umar consulted with his advisors from%0D%0Athe companions on the starting date of the new Muslim calendar. It was%0D%0Afinally agreed that the most appropriate reference point for the Islamic%0D%0Acalendar was the Hijrah the incident of the immigration of the Muslims from%0D%0AMakkah to Madinah. It is a central historical event of early Islam that led%0D%0Ato the foundation of the first Muslim city-state, a turning point in Islamic%0D%0Aand world history. The actual starting date for the calendar was chosen (on%0D%0Athe basis of purely lunar years, counting backwards) to be the first day of%0D%0Athe first month (1 Muharram) of the year of the Hijrah. The Islamic (Hijri)%0D%0Acalendar (with dates that fall within the Muslim Era) came to be abbreviated%0D%0Aby some as AH in Western languages from the latinized Anno Hegirae, "in the%0D%0Ayear of the Hegira". Muharram 1, 1 AH therefore corresponds to July 16, 622%0D%0ACE.%0D%0A%0D%0AThe Islamic year consists of twelve (purely lunar) months. They are:%0D%0AMuharram; Safar; Rabi'ul Awwal; Rabi'uth Thani; Jumada al-Awwal; Jumada%0D%0Aath-Thani; Rajab; Sha'ban; Ramadhan; Shawwal; Thul Qi'dah; and THUL HIJJAH.%0D%0ASome of the most important dates in the Islamic year are: 1 Muharram%0D%0A(Islamic new year); 1 Ramadhan (first day of fasting); 1 Shawwal (Eidul%0D%0AFitr); 8-10 Thul Hijjah (the Hajj to Makkah); and 10 Thul Hijjah (Eidul%0D%0AAdh-ha).%0D%0A%0D%0ATo Muslims, the Hijri calendar is more than a sentimental system of time%0D%0Areckoning, and dating important religious events. Many of the marital and%0D%0Aspousal relationship rulings of the women are directly connected to the%0D%0Alunar (Islamic) months. The Hijri calendar, therefore, has a much deeper%0D%0Areligious and historical significance in the Muslim life. Muhammad Ilyas in%0D%0Ahis book, "A Modem Guide to Astronomical Calculations of Islamic Calendar,%0D%0ATimes & Qiblah," quoted Abul Hassan an-Nadwi who wrote, "It (the advent of%0D%0Athe 15th Islamic century) is indeed, a unique occasion to ponder that the%0D%0AIslamic Era did not start with the victories of Islamic wars, nor with the%0D%0Abirth or death of the Prophet, sallallahu alayhi wasallam, nor with the%0D%0ARevelation itself. It starts with Hijra, or the sacrifice for the cause of%0D%0ATruth and for the preservation of the Revelation. It was a divinely inspired%0D%0Aselection. Allah wanted to teach Man that the struggle between Truth and%0D%0AEvil is eternal. The Islamic year reminds Muslims not of the pomp and glory%0D%0Aof Islam but of its sacrifice, and prepares them to do the same." From a%0D%0Ahistorical angle, Ilyas quoted Samiullah who wrote, "All the events of%0D%0AIslamic history, especially those that took place during the life of the%0D%0AProphet, sallallahu alayhi wasallam, and afterwards are quoted in the Hijra%0D%0Acalendar era. But our calculations in the Gregorian calendar keep us away%0D%0Afrom those events and happenings, which are pregnant of admonitory lessons%0D%0Aand guiding instructions. ...And this chronological study is possible only%0D%0Aby adopting the Hijri calendar to indicate the year and the lunar month in%0D%0Aline with our cherished traditions."%0D%0A%0D%0AWHY USE THE ISLAMIC CALENDAR?%0D%0AMuslims are obliged to use the Islamic calendar because all of the rulings%0D%0Aneeding time tracking are related to it. They should use a calendar with 12%0D%0Alunar months without intercalation as evident from the following verses of%0D%0Athe Qur'an, "They ask you about the New Moons, say they are but signs to%0D%0Amark fixed periods of time in (the affairs of) men and for Hajj." [11:189]%0D%0A%0D%0A"The number of months in the sight of Allah is twelve (in a year) so%0D%0Aordained by Him the day He created the heavens and the earth. Of them four%0D%0Aare sacred; that is the straight usage so wrong not yourselves therein, and%0D%0Afight the pagans." [9:36]%0D%0A%0D%0A"Verily the transposing (of a prohibited month) is an addition to unbelief:%0D%0Athe non-believers are led to wrong thereby: for they make it lawful one%0D%0Ayear, and forbidden another year, of months forbidden by Allah and make such%0D%0Aforbidden ones lawful. The evil of their course seems pleasing to them. But%0D%0AAllah guides not those who reject Faith." [9:37]%0D%0A%0D%0ASince the Islamic calendar is purely lunar, the Muslim year is shorter than%0D%0Athe Gregorian year by about 11 days. Also, the months of the Islamic year%0D%0Aare not related to seasons which are fundamentally determined by the solar%0D%0Acycle. This means that important Muslim festivals, which always fall in the%0D%0Asame lunar month, will occur in different seasons. For example, the Hajj and%0D%0ARamadhan's fasting can take place in the summer as well as the winter. It is%0D%0Aonly over a 33 year cycle that lunar months take a complete turn and fall%0D%0Aduring the same season.%0D%0A%0D%0AFor religious reasons, the beginning of a lunar month is marked not by the%0D%0Abirth of a new moon, but by a physical (i.e. an actual human) sighting of%0D%0Athe crescent moon at a given locale. From the Fiqh standpoint, one may begin%0D%0Athe fast in Ramadhan, for example, based on a "local" sighting. This also%0D%0Aknown as Ikhtilaful Matali' (separate horizons) or the recognition that%0D%0Adifferent part of the world may have different (unrelated) sightings of the%0D%0Amoon as in the case when the two places do not share days or nights. Or%0D%0Abased on a "global" sighting anywhere in the world. This is the case known%0D%0Aas Ittihadul Matali' (single horizon) where one sighting of the new moon is%0D%0Aconsidered to be valid for beginning the month for all parts of the world.%0D%0AAlthough different, both of these positions are valid Fiqh positions.%0D%0A%0D%0AAstronomically, some data are definitive and conclusive (i.e., the birth of%0D%0Athe new moon). However, determining the visibility of the crescent is not as%0D%0Adefinitive or as conclusive; rather it is dependent upon several factors,%0D%0Amostly optical in nature. Therefore, all Islamic calendars are to be updated%0D%0Aevery month to insure the exact beginning of each month. This should not%0D%0Apresent difficulties in using the calendar as a planning tool. Muslims have%0D%0Adevised some methods to calculate the approximate beginning of the months%0D%0A(i.e., predicting the sightability of the new moon at the different parts of%0D%0Athe world) and in turn used them to produce calendars.%0D%0A%0D%0AAl-Jumu'ah Vol.11 Issue1