who accompanied the prophet on his migration to madinah
Hegira The Hegira, Hijrah or Hijrath (Arabic: هِجْرَة‎) is the migration or journey of the Islamic prophet Muhammad and his followers from Mecca to Yathrib, later renamed by him to Medina, in the year 622.[1] In June 622, after being warned of a plot to assassinate him, Muhammad secretly left his home in Mecca to emigrate to Yathrib, 320 km (200 mi) north of Mecca, along with his companion Abu Bakr.[6] Yathrib was soon renamed Madīnat an-Nabī (Arabic: مَـديـنـة الـنّـبي‎, literally "City of the Prophet"), but an-Nabī was soon dropped, so its name is "Medina", meaning "the city".[7]
Siege of Jerusalem (636–637) In 634, Abu Bakr died and was succeeded by Umar, who continued his own war of conquest.[5] In May 636, Emperor Heraclius launched a major expedition to regain the lost territory, but his army was defeated decisively at the Battle of Yarmouk in August 636. Thereafter, Abu Ubaidah, the Muslim commander-in-chief of the Rashidun army in Syria, held a council of war in early October 636 to discuss future plans. Opinions of objectives varied between the coastal city of Caesarea and Jerusalem. Abu Ubaidah could see the importance of both these cities, which had resisted all Muslim attempts at capture. Unable to decide on the matter, he wrote to Caliph Umar for instructions. In his reply, the caliph ordered them to capture the latter. Accordingly, Abu Ubaidah marched towards Jerusalem from Jabiya, with Khalid ibn Walid and his mobile guard leading the advance. The Muslims arrived at Jerusalem around early November, and the Byzantine garrison withdrew into the fortified city.[1]