Jul 2 Incident at Xuanwu Gate: in fear of assassination, Li Shimin ambushes and kills his rival brothers Li Yuanji and Li Jiancheng Jul 29 Avars under khagan Bajan begin siege of Constantinople (fails, preserving the eastern Roman empire) Aug 7 Battle at Constantinople: Slavic/Persians/Avarenvloot defeated Sep 4 Shimin becomes Emperor Taizong of Tang, Emperor of China, when his father abdicates in his favour 625 AD Events in History by Year 627 AD