600s | dp2=610s | dp1=620s | d=630s | dn1=640s | dn2=650s | dn3=660s }} Events By Place Oswald of Northumbria defeats Cadwallon ap Cadfan of Gwynedd in the Battle of Heavenfield and reunites Northumbria. Asia The Rashidun Caliphate starts the Islamic conquest of the Byzantine empire. September 20 — Khalid Ibn Walid captures Damascus. The Xianbei/Tibetan state of Tuyuhun's invaded by Tang Dynasty China during Emperor Taizong's campaign against Tuyuhun, led by commander Li Jing,… (More on 634)