The T’ang Dynasty was founded in 618 by Li Yuan and his son Li Shih-min. The T’angs dynasty used Loyang and Ch’ang-an as eastern and western capitals. The basic administrative organization of the Tang dynasty would guide China until the 20th century.
At the battle of Nineveh, the forces of Heraclius (the Byzantine Emperor), defeated the forces of the Sassanid Empire. The Persian forces were led by Khosrau II. The victory saved the Byzantine Empire from further Persian attack.
Omar began a campaign against the Byzantines. The Arab forces defeated the Byzantines at the Battle of Yarmuk. The Arabs took Damascus and Emessa. In 638 Jerusalem surrendered to Omar’s forces. Ceasaria and Aleppo were soon taken as well.
Arab forces under the command of Amir ibn al-As attacked Egypt. In 642, under terms arranged by Cyrus, Patriarch of Alexandria, Egypt surrendered. Terms of the agreement included guaranteed security for people and property, as well as freedom of religion. All this was to be obtained in return for the payment of tribute.