Thread by @Ubaidbinriyaz

@Hadithoftheday Umar Ibn Al Khattab R.A.
The Islamic calendar was first introduced during the era of the Amir Al-Mu’mineen, or, Umar ibn Al-Khattaab R.A during the 16th or 17th year after the Hijrah, (migration of the Prophet Muhammad ﷺ)

@Hadithoftheday It was only six years after the Prophet ﷺ that Umar R.A in 17th AH consulted the learned and canonized the Year of Hijrah, as suggested by Ali Ibn Abi Talib, as the beginning of Islamic era.

@Hadithoftheday Uthman bin Affan R.A suggested that the year might begin from the month of Muharram after Haj, which was approved. Thus the first year of Hijrah (1 AH) began from Muharram 1.

@Hadithoftheday After consulting the Prophet’s Companions, Umar Ibn al-Khattab R.A established the year of the Prophet’s emigration as the beginning of the Islamic calendar since it was the single most important event in the Islamic world at that time.

@Hadithoftheday Umar R.A sought the people’s advice on when the Hijri calendar should start. Some held that it should have started from the birth of the Prophet ﷺ, whilst others thought that it should have begun from the very first day that the Messenger of Allah ﷺ began his mission. +

@Hadithoftheday Another group believed that the calendar should have started from the emigration and the last group held that the calendar should have begun from the death of the Prophet ﷺ.
Umar R.A agreed with those who wished to start the Islamic calendar with the Hijrah of the Prophet ﷺ .+

@Hadithoftheday This was due to the fact that "Hijrah" marked the point in history when Allah differentiated between truth and falsehood by giving the Prophet ﷺ real power and authority which was manifested in the form of the first Islamic state.

@Hadithoftheday The Hijrah, historically is the central event of early Islam, the turning point in Islamic history that led to the foundation of the first Muslim state.
Thus, The Hijri calendar was officially created during the reign of Umar ibn al-Khattab R.A.

@Hadithoftheday There are 12 months in the Islamic calendar/Hijri Calender.
They are:

1. Muharram
2. Safar
3. Rabi'i-Al-Awwal
4. Rabi'i-Al-Thani
5. Jumad-Al-Awwal
6. Jumad-Al-Thani
7. Rajab
8. Sha'ban
9. Ramadan (Month of Fasting)
10. Shawwal
11. Dhul-Qa'ada
12. Dhul Hijjah (Month of Hajj)

@Hadithoftheday The Hijri calendar is based on a lunar month of 29 to 30 days, with the day starting at sunset.
The Islamic calendar is lunar, its year is 10 or 11 days shorter than the Gregorian year. This means that these months fall in different seasons.

@Hadithoftheday Allah says in Qur'an:

They ask you, (O Muhammad), of new moons. Say: They are fixed seasons for mankind and for the pilgrimage… (Qur'an 2:189)