636

Year 636 was a leap year starting on Monday of the Julian calendar. The denomination 636 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.

Events

Arab–Byzantine War: Emperor Heraclius assembles a large army consisting of contingents of Byzantines, Slavs, Franks, Georgians, Armenians, and Christian Arabs. He establishes a base at Yaqusah, close to the edge of the Golan Heights, protecting the vital main road from Egypt to Damascus. The base is protected by deep valleys and precipitous cliffs, well supplied with water and grazing.
Summer - Heraclius summons a church assembly at Antioch, and scrutinises the situation. He accepts the argument that Byzantine disobedience to God is to blame for the Christian disaster in Syria. Heraclius leaves for Constantinople with the words, Peace be with you Syria — what a beautiful land you will be for your enemy.

April 28 - Yuknoom Chʼeen II becomes the ruler of the Mayan city state of Calakmul in southern Mexico and reigns for 50 years until his death in 686.

Chintila is elected by a convention of bishops and nobles as ruler of the Visigoths, after the death of King Sisenand.
Rothari marries widowed Queen Gundeberga, and succeeds Arioald as king of the Lombards. During his reign, he puts many insubordinate nobles to death.

August 15-20 - Battle of Yarmouk: In engagements along the Yarmouk River, Muslim forces of the Rashidun Caliphate, led by Khalid ibn al-Walid, decisively defeat the armies of the Byzantine Empire, effectively completing the Muslim conquest of Syria. It will be regarded as one of the most decisive battles in military history, marking the first great wave of Muslim conquests, after the death of Muhammad.
The city of Basra is founded on the Shatt al-Arab, at the head of the Persian Gulf. The port will become a major trading center for commodities from Arabia, India, and Persia.
November 16-19 - Battle of al-Qādisiyyah: The Muslim Arab army defeats the Persian forces under Rostam Farrokhzād, at Al-Qādisiyyah.

The historical texts of the Book of Northern Qi, Book of Chen, and Book of Sui are compiled in China, during the Tang dynasty.

Birinus, Bishop of Dorchester, converts Cwichelm to Christianity. He dies soon afterward, and is supposedly buried at Scutchamer Knob, in East Hendred.
June 30 - Fifth Council of Toledo: Chintila orders a meeting in the church of St. Leocadia; the bishops accept a decree that only Gothic nobility may be king of the Visigothic Kingdom.