637 CE
Siege of Ctesiphon: The Rashidun army (15,000 men) under Saʿd ibn Abi Waqqas occupies the Persian capital of Ctesiphon, after a two-month siege. King Yazdegerd III flees with the imperial treasure eastward into Media. Muslim forces conquer the Persian provinces as far as Khuzestan (modern Iran). Battle of Mag Rath: King Oswald of Northumbria sends troops to Ireland, to assist Domnall Brecc King of Dál Riata in his alliance with King Congal Cáech of Ulaid against Domnall mac Áedo High King of Ireland, during the Irish dynastic wars. Domnall Brecc, Congal and their forces are defeated near Moira. At the Mull of Kintyre (southwest Scotland), Domnall mac Áedo's fleet destroys Domnall Brecc's naval force of Dál Riata. Siege of Aleppo: Muslim Arabs under Khalid ibn al-Walid conquer the Byzantine stronghold Aleppo; the large walled city surrenders after a four-month siege. A column of troops under Malik al-Ashtar is sent to take Azaz.
Conflict & Security
- March – Siege of Ctesiphon: The Rashidun army (15,000 men) under Saʿd ibn Abi Waqqas occupies the Persian capital of Ctesiphon, after a two-month siege. King Yazdegerd III flees with the imperial treasure eastward into Media. Muslim forces conquer the Persian provinces as far as Khuzestan (modern Iran).source
- April – Siege of Jerusalem: The Rashidun army (20,000 men), led by 'Amr ibn al-'As, conquers Jerusalem after a six-month siege. The Byzantine garrison surrenders to Caliph Umar I, who is invited by Sophronius, patriarch of Jerusalem, to pray in the Church of the Holy Sepulchre. Umar declines, fearing that accepting the invitation might endanger the church's status, and turn the Christian holy site into a mosque.source
- June 24 – Battle of Mag Rath: King Oswald of Northumbria sends troops to Ireland, to assist Domnall Brecc King of Dál Riata in his alliance with King Congal Cáech of Ulaid against Domnall mac Áedo High King of Ireland, during the Irish dynastic wars. Domnall Brecc, Congal and their forces are defeated near Moira. At the Mull of Kintyre (southwest Scotland), Domnall mac Áedo's fleet destroys Domnall Brecc's naval force of Dál Riata.source
- October – Siege of Aleppo: Muslim Arabs under Khalid ibn al-Walid conquer the Byzantine stronghold Aleppo; the large walled city surrenders after a four-month siege. A column of troops under Malik al-Ashtar is sent to take Azaz.source
- Battle of the Iron Bridge: Rashidun forces under Khalid ibn al-Walid defeat the Byzantine army and Christian Arabs near Antioch, at the Orontes River. It marks the complete annexation of Syria into the Rashidun Caliphate.source
- Battle of Jalula: Muslim Arabs defeat the Persian forces (20,000 men) under Farrukhzad at the Diyala River. The cities Tikrit and Mosul are captured, completing the conquest of Mesopotamia. The region west of the Zagros Mountains is annexed by the Rashidun Caliphate.source
- Chang'an, capital of the Tang dynasty (China), becomes the largest city of the world, taking the lead from Ctesiphon, capital of Persia.source
- Battle of Hazir: Muslim Arab forces (17,000 men) under Khalid ibn al-Walid defeat the Byzantine army near Qinnasrin (Northern Syria). The cities of Beirut and Tyre are captured by Yazid ibn Abi Sufyan after a short siege.source
Religion & Belief
- The Muslims replace Zoroastrianism with Islam in Mesopotamia (later Iraq); they do not force their conquered subjects to embrace the Islamic faith, but they do require acceptance of the Quran as the doctrine of divine teaching, and will oblige their subjects to learn Arabic (approximate date).source
Technology & Infrastructure
- King Songtsän Gampo builds the first palace on the site of the Potala Palace in Lhasa (Tibet).source
Science & Discovery
- Queen Seondeok of Silla (Korea) builds an astronomical observatory near Gyeongju (Cheomseongdae), one of the oldest in East Asia.source
Deaths
- Congal Cáech, high king of Dál nAraidi (Ireland)source
- Andreas of Caesarea, bishop and writer (b. 563)source
- Wen Yanbo, chancellor of the Tang dynasty (b. 575)source
- Maria al-Qibtiyya, concubine of Muhammadsource
- Mo Chua, Irish bishop and founder of Ballasource
- John Athalarichos, illegitimate son of Heracliussource
- Mo Chutu, Irish abbot and founder of Lismore Abbeysource
- Rostam Farrokhzād, Persian general (or 636)source