This Julian calendar was used throughout Europe until 1582 ce. Consulting Greek astronomers in Alexandria, he created a solar calendar in which one day was added to February every fourth year, effectively compensating for the solar year’s length of 365.2422 days. By 46 bce, it was some three months out of alignment, and Julius Caesar oversaw its reform. The system for doing so was complex, and cumulative errors gradually misaligned it with the seasons. To keep it more or less in accord with the actual solar year, a month was added every two years. The early Roman calendar was lunisolar, containing an average 355 days divided into 12 months. This 11-day difference between the lunar and the solar year accounts for the difficulty of converting dates from one system to the other. Its festivals, which fall on the same days of the same lunar months each year, make the round of the seasons every 33 solar years.

(This date corresponds to July 16, 622 ce, on the Gregorian calendar.) Today in the West, it is customary, when writing hijri dates, to use the abbreviation ah, which stands for the Latin anno hegirae, “year of the hijra.”īecause the Islamic lunar calendar is 11 days shorter than the solar, it is therefore not synchronized to the seasons. The hijra thus occurred on 1 Muharram of the year 1 according to the Islamic calendar, which was named “hijri” after its epoch. ‘Umar chose as the epoch for the new Muslim calendar the hijra, the emigration of the Prophet Muhammad and 70 Muslims from Makkah to Madinah, where Muslims first attained religious and political autonomy. This gives the lunar year 354 days, 11 days fewer than the solar year. It would be lunar, and it would have 12 months, each with 29 or 30 days. He therefore decided to create a calendar specifically for the Muslim community. Not only that, calendars used by the Persians, Syrians and Egyptians were identified with other religions and cultures. The Qur’an, in Chapter 10, Verse 5, states that time should be reckoned by the moon. There were two other reasons ‘Umar rejected existing solar calendars. The names of the months in that calendar have continued in the Islamic calendar to this day and would seem to indicate that, before Islam, some sort of lunisolar calendar was in use, though it is not known to have had an epoch other than memorable local events. In central Arabia, the course of the year was charted by the position of the stars relative to the horizon at sunset or sunrise, dividing the ecliptic into 28 equal parts corresponding to the location of the moon on each successive night of the month. On the eve of Islam, the Himyarites appear to have used a calendar based on the Julian form, but with an epoch of 110 bce. In South Arabia, some calendars apparently were lunar, while others were lunisolar, using months based on the phases of the moon but intercalating days outside the lunar cycle to synchronize the calendar with the seasons. In pre-Islamic Arabia, various other systems of measuring time had been used.

Although all were solar calendars, and hence geared to the seasons and containing 365 days, each also had a different system for periodically adding days to compensate for the fact that the true length of the solar year is not 365 but 365.2422 days. Egypt used the Coptic calendar, with an epoch of August 29, 284 ce. Syria, which until the Muslim conquest was part of the Byzantine Empire, used a form of the Roman “Julian” calendar, with an epoch of October 1, 312 bce. The Sasanids, the ruling dynasty of Persia, used June 16, 632 ce, the date of the accession of the last Sasanid monarch, Yazdagird iii. Each of these calendars had a different starting point, or epoch. But Persia used a different calendar from Syria, where the caliphate was based Egypt used yet another. Correspondence with military and civilian officials in the newly conquered lands had to be dated. This was first of all a practical matter. In 638 ce, six years after the death of the Prophet Muhammad, Islam’s second caliph, ‘Umar, recognized the necessity of a calendar to govern the affairs of Muslims. Qur‘an 10:5 (English by Yusuf Ali) The Hijri calendar “It is he who made the sun to be a shining glory, and the moon to be a light (of beauty), and measured out stages for her, that ye might know the number of years and the count (of time).”

Ramadan 2016 islamic calendar