10 events the sources record for this year, grouped by region.
What happened
China (5)
Emperor Xianzong died at the age of 43 at Zhonghe Hall in Daming Palace (there is a theory that he was assassinated by the eunuch Chen Hongzhi). (Old Book of Tang (Jiu Tangshu), Annals 舊唐書 卷15 元和15年 1月)
A letter to the Balhae king was issued, noting that the previous envoy Kamtok (感徳) and others could not come because their ship had drifted, and that a single ship had been specially sent for them. (Nihon Kōki (Later Chronicles of Japan) 日本後紀 卷28)
About 700 Silla people settled in Tōtōmi and Suruga rebelled, killed people and set houses on fire. The forces of the two provinces could not defeat them; when they stole grain from Izu Province and put out to sea by boat, troops of seven provinces including Sagami and Musashi were sent to pursue them, and all were pacified. (Nihon Kōki (Later Chronicles of Japan) 日本後紀 卷28)
Western Europe (3)
At the January assembly at Aachen it is decided to send three armies against Riudewit. Bera, count of Barcelona, loses a duel and is sentenced to death, but by the emperor's mercy his sentence is commuted to exile at Rouen (Royal Frankish Annals ARF a.820, Kurze 1895 p.152)
In spring the three armies set out against Riudewit: from Italy over the Noric Alps, through the Carantani region, and into Bavaria and Upper Pannonia. The middle army overcomes resistance in three places and crosses the Drava, but Riudewit shuts himself up in a hilltop fort and will not respond. The armies devastate the region with fire and sword and return, though the Upper Pannonian army suffers heavy losses from dysentery (Royal Frankish Annals ARF a.820, Kurze 1895 p.152)
Continuous rain and humidity spread a plague among people and cattle throughout the Frankish kingdom; the grain rots and the wine turns sour (Royal Frankish Annals ARF a.820, Kurze 1895 p.154)