The History of the Islamic Calendar: Follow the Moon!

Today the clock fell back one hour here in the USA! A debate raged in my household between my son and spouse regarding if we in fact gained or lost an hour.  And recently I have been talking to friends about the Mayan Calendar and how according to that calendar the world is supposedly coming to an end in 2012! And I have been reading recently a lot on Islamic banking and finance topics in which texts continually reference, compares and contrasts, dates from the Gregorian and Islamic Calendar.   These calendar and data/time encounters got me interesting in learning more about both the Gregorian and the Islamic calendars.  The BH, AH, BC, AD and a whole lot of two letter designations and gaps in years got me totally confused.  So here is what I found so far and I hope it help you folks who cross between two worlds (maybe more!)

To find a frame of reference on where do we really stand today in this very moment (what is the date, time, and in reference to what exactly), we always need an absolute moment in time to serve as the relative reference.  This might be a simplistic or even moronic post ...but for me, I need to STOP my own confusion and learn about these calendars frame of reference and how they compare or differ.  So here is what I learned this morning:

Islamic Calendars: We awe it to Caliph Umar and to an event that occurred in 638 which corresponds to 17 years after Prophet Muhammad Hijra (flight) to Medina from Kaaba.  Abu-Musa al-Sha'ari complained to Umar about his lack of ability to reference the correspondence he is receiving (instructions) to a date so that he would know what came first or last.   This complaint and the overall expansion of the Islamic world and the need to make sure all Islamic posts get dated correspondence convinced Umar an Islamic Calendar is necessary.   He debated with his advisers, consulted, discussed, and finally he decided to start the Islamic Calendar with the year of Muhammad's Hijra to Medina.  Though Umar choose the year of the Hijra, he did not start the year on the date of Hijra itself which happened in September.  He started the Islamic Calendar on July 16, 622 C.E which corresponds to Muharram, the first month of the year by Arab custom at the time.  On this day of Muharram 1, 1 A.H Muslims began their calendar count and today November 1, 2009 is considered the 13th of al-Qi`dah 1430 A.H in the Islamic world.  The conversion calculator has one day error margin, however.  If you would like to play with dates and conversions in an islamic calendar try this site: http://www.islamicfinder.org/Hcal/hdate_gr.php.  The reason why you need a conversion calculator is there is no fixed translation relationship between the Gregorian months and the Islamic months. 

The calculation depends on the moon and astronomy and a whole lot of complicated things I can not claim to understand.  So Muharram could happen in June or September or December or any other month over the course of time depending on the Islamic Calendar date.  And this may explain why Ramadan does not always come on the same month of the Gregorian Calendar.  It keeps on moving in reference!   The moon is to blame for this complication! The Gregorian calendar is fixed on the solar system.  The Islamic Calendar follows the moon and each month's start is observed when the crescent appears at the beginning of each Islamic month. 

Here are the months in the Islamic Calendar:

1. Muharram محرّم (or Muḥarram al Ḥaram)
2. Safar صفر (or Ṣafar al Muzaffar)
3. Rabi' al-awwal (Rabī' I) ربيع الأول
4. Rabi' al-thani(or Rabī' al Thānī, or Rabī' al-Akhir) (Rabī' II) ربيع الآخر أو ربيع الثاني
5. Jumada al-awwal(Jumādā I) جمادى الاول
6. Jumada al-thani(or Jumādā al-akhir) (Jumādā II) جمادى الآخر أو جمادى الثاني
7. Rajabرجب (or Rajab al Murajab)
8. Sha'abanشعبان (or Sha'abān al Moazam)
9. Ramadanرمضان (or Ramzān, long form: Ramaḍān al Mubarak)
10. Shawwalشوّال (or Shawwal al Mukarram)
11. Dhu al-Qi'dah ذو القعدة
12. Dhu al-Hijjah