Fast was obligatory in 2nd Hijri.
Muslim keep fast in month of Ramzan
Ramadan is divided into three stages-first Ashra (Rehmat), second Ashra (Maghfirat) and the third Ashra (Nijaat).

******

Must remember all 12 Islamic months name

List of Islamic Months

1. Muḥarram, محرم الحرام
   
2. Ṣafar, صفر المظفر
3. Rabi al Awwal ربیع الاول
4. Rabi al Sani ربیع الثانی
5. Jumada al Awwal جمادی الاول
6. Jumada al Thani جمادی الثانی
7. Rajab, رجب المرجب
8. Shabanشعبان المعظم
9. Ramadan(fasting), رمضان المبارک
10. Shawwal شوال المکرم
11. Dhu al Qadah ذوالقعدۃ الحرام
12. Dhu al Hijjah ذوالحجۃ الحرام:

Each month begins approximately at the time of the new moon.

RK220123

Prophet Muhammed (Sallallahu Alaihi Wasallam)  Born: Mecca, Saudi Arabia

Prophet Muhammed (Sallallahu Alaihi Wasallam) Died: June 8, 632 AD, Medina, Saudi Arabia

Namaz Juma Became Farz In Madina.

Abū Isḥāq Muḥammad ibn Hārūn al-Rashīd better known by his regnal name al-Muʿtaṣim biʾllāh, was the eighth Abbasid caliph, ruling from 833 until his death in 842. A younger son of Caliph Harun al-Rashid, he rose to prominence through his formation of a private army composed predominantly of Turkic slave-soldiers.

Umm al-Qura refer to the city of Mecca in Saudi Arabia.

Musaylimah fought and was killed in the Battle of Yamama by Wahshi ibn Harb,

the same man (Wahshi ibn Harb) who had killed Muhammad's uncle, Hamza, in the battle of Uhud before his conversion to Islam

Jannat al-Baqīʿ is the oldest and the first Islamic cemetery of Medina in the Hejazi region of present-day Saudi Arabia. It is located to the southeast of the Prophet's Mosque, which contains the graves of some of Prophet Muhammad's family and friends. It is also known as Baqīʿ al-Gharqad.

Al-Mawardi was one of the most famous thinkers in political science in the middle Ages. He was also a great sociologist.
Ambassador of the Abbasid Caliph to several important and powerful Muslim states.