The world in 801 AD — what happened that year

9 events the sources record for this year, grouped by region.

What happened

The Tibetans took Lin Prefecture, killed its prefect Guo Feng, smashed the battlements, and withdrew. (Old Book of Tang (Jiu Tangshu), Annals 舊唐書卷13 貞元17年 7月)
The Tibetans captured Linzhou; Prefect Guo Feng was killed in battle. (New Book of Tang (Xin Tangshu), Annals 新唐書卷007 德宗·順宗·憲宗貞元17年7月)
Fujiwara no Kadonomaro was appointed envoy to Tang (kentōshi), with Ishikawa no Michimasu as deputy. (Nihon Kōki (Later Chronicles of Japan) 日本後紀卷10)
Tibetans take Linzhou and kill its prefect Guo Feng. (Zizhi Tongjian (Comprehensive Mirror) 資治通鑑卷236)
Wei Gao besieges Weizhou and the Kunming fortress. (Zizhi Tongjian (Comprehensive Mirror) 資治通鑑卷236)

Tamna sent envoys to pay tribute. (Samguk Sagi (History of the Three Kingdoms) 卷10 哀莊王 2年)

The general Sakanoue no Tamuramaro and others report: the Emishi bandits were subdued and submitted (the original abbreviates the rest with 'and so on'). (Nihon Kōki (Later Chronicles of Japan) 日本後紀卷10)
Edict: the Emishi of Mutsu had for generations invaded the frontier and harmed the people; Tamuramaro and others were sent and pacified them. Tamuramaro was raised to Junior Third Rank. (Nihon Kōki (Later Chronicles of Japan) 日本後紀卷10)

Harun goes on pilgrimage and divides the empire among his three sons — the decree hung on the Kaaba (Al-Tabari, History of the Prophets and Kings Series III tom.2 (Arg.) [india.history.resource.86977], Annus 186)