13 events the sources record for this year, grouped by region.
What happened
China (7)
Huang Chao, a bandit of Yuanqu, attacked Yunzhou with ten thousand men, took it, and drove out Jiedushi Xue Chong. (Old Book of Tang (Jiu Tangshu), Annals 舊唐書 卷19下 乾符4年)
Huang Chao, a bandit from Wanju, captured the prefectures of Yunzhou and Yizhou; Xue Chong, the Tianping Army governor, was killed in battle. (New Book of Tang (Xin Tangshu), Annals 新唐書 卷009 懿宗·僖宗 乾符4年3月)
On the third day of the first month, Emperor Yōzei ascends the throne at the Buraku-den, since the Daikyokuden has not yet been rebuilt, and proclaims an edict. (Nihon Sandai Jitsuroku 卷第三十 元慶元年1月 (원문 30.32))
On the ninth day of the fourth month, at the hour of the snake, reconstruction of the Daikyokuden begins. Princes and courtiers, with the carpenters led by Hitan, entertain at the Hasshōin the officials in charge of the work and the craftsmen. (Nihon Sandai Jitsuroku 卷第卅一 元慶元年4月九日 (원문 31.12))
Bohai envoys led by Yang Zhongyuan return home from Izumo province. The royal letter (kei) and the sacred objects are not accepted and are sent back; the cup of tortoiseshell (taimo) that the chief envoy wished to present is also refused. (Nihon Sandai Jitsuroku 卷第卅一 元慶元年廿五日 (원문 31.76))
On the twenty-second day of the eighth month, Dazaifu reports that on the twenty-fifth day of the seventh month 63 Tang merchants led by Cui Duo arrived at Chikuzen from Taizhou in Tang, carrying Japanese envoys including Tan'ankō. By custom they are lodged and supplied. (Nihon Sandai Jitsuroku 卷第卅二 元慶元年8月廿二日 (원문 32.42))
Western Europe (1)
The Danish army went from Wareham to Exeter; the fleet lost 120 ships in the fog at Swanwich; Alfred took hostages and received their oath. (Anglo-Saxon Chronicle Giles/Ingram 1847 A.D. 877 항 (pg657.txt 줄 2859))