Cultures and religions around the world celebrate various new years with calendars mostly spanning over 12 months, of which the most widely used today is the Gregorian calendar. The dating system formally began approximately after the acceptance of Jesus Christ son of Mary (peace be upon them) and belief in Christianity. It follows the solar system of counting days, which indicates the position of the Earth’s revolution around the sun. Excluding leap years, there are 365 days in a Gregorian calendar, and soon enough we will be entering the 2017th year, AD.
Meanwhile, 1438 years ago, coinciding with September 622 AD, the Prophet Mohammad (peace be upon him) emigrated from Mecca to Medina and marked a new way of life for Muslims. This act, known as “the Hijrah” in Arabic, introduced the Islamic calendar and is now followed by Muslims all over the world daily, and to know when to celebrate the holy festivals.
“They ask thee concerning the New Moons. Say: They are but signs to mark fixed periods of time in (the affairs of) men, and for Pilgrimage. It is no virtue if ye enter your houses from the back: It is virtue if ye fear Allah. Enter houses through the proper doors: And fear Allah. That ye may prosper.” (Quran 2:189)
As the Gregorian calendar, there are 12 months in the Hijri calendar and the year begins from the month of Muharram and ends at the month of the Hajj pilgrimage, Dhul Hijja. However, contrary to the Gregorian calendar, the Hijri calendar is based on lunar calculations. It follows the phases and cycle of the moon and is about 354 days, 11 days shorter than the solar calendar. This year, the Islamic New Year will begin in the evening of October 2nd.
“The number of months in the sight of Allah is twelve (in a year)ـ so ordained by Him the day He created the heavens and the earth; of them four are sacred: that is the straight usage. So wrong not yourselves therein, and fight the Pagans all together as they fight you all together. But know that Allah is with those who restrain themselves.” (Quran 9:36)
The reason why the event of Hijrah was chosen as the start of the calendar, instead of the Prophet’s birthday, for example, or another significant event such as the start of the Revelation, is because this event marks the launch of the first Islamic state (Medina). The state broke “blood ties” as the formal organization of community to incorporate the Muslim community as a whole.
Before the Hijrah, in 621 AD, the Prophet Mohammad (peace be upon him) and the Muslims faced severe prosecution from the pagan tribes of Mecca, ranging from harassment to torture. To insure their safety, the Prophet sent some of his followers to the Kingdom of Axum (Ethiopia today) where they could be protected, and sent others to the town of Yathrib (known today as Medina, ”the city” in English), north of Mecca.
According to Islamic history, the Prophet Mohammad himself did not leave with his followers and, approximately a year later, he learned of a plot to assassinate him. So, with his closest companion, Abu Bakr Alـ-Siddiq, he went off to join the emigrants in Medina. Ali, the Prophet’s cousin, took Mohammad’s place in his home and slept in his bed.
When the Meccan tribes arrived at the Prophet’s home and found that he escaped, they set off after him. However, Mohammad and Abu Bakr took refuge in a cave. As they were hiding, a spider spun its web across the opening of the cave, which misled the Meccans to believing that no one could possibly be in there and passed by, allowing Mohammad and Abu Bakr to go on to Medina where the Muslims became free to start an organized Islamic society based on brotherhood and faith. That year became the designated first year of the Islamic calendar and is marked by H or AH (Anno Hegirae in Latin).
In pagan Arabia, the people used a lunisolar calendar. It used lunar months but was also accorded with the seasons by the insertion of an additional intercalary month, which is the insertion of a leap day, week or month into some calendar years to make the calendar follow the seasons or moon cycles, when required.
However, in the ninth year after the Hijrah, Allah formally revealed to the Muslims the prohibition of the use of intercalary months as well as the months of the Islamic calendar forbidden to fight in:
“Verily the transposing (of a prohibited month) is an addition to Unbelief: the Unbelievers are led to wrong thereby: for they make it lawful one year, and forbidden another year, in order to adjust the number of months forbidden by Allah and make such forbidden ones lawful. The evil of their course seems pleasing to them. But Allah guideth not those who reject Faith.” (Quran 9:37)
Lunar sightings differ from country to country and the Islamic New Year varies slightly between, for example, countries in Africa and countries in Asia. However, regardless, Muslims all over the world use the calendar to mark celebrations such as Ramadan, Eid Alـ-Fitr, Eid Alـ-Adha and Hajj, so that everyone maybe united and in accordance to Islam.
Happy New Year – 1438 AH.
In Conclusion 
Very well written 👍