18 events the sources record for this year, grouped by region.
What happened
China (8)
Liu Wu beheaded Li Shidao and his son and surrendered, and the twelve prefectures of Zi-Qing were pacified. (Old Book of Tang (Jiu Tangshu), Annals 舊唐書 卷15 元和14年)
When Emperor Xianzong of Tang raised troops to attack Li Sidao of Yunzhou, King Heondeok sent Kim Ungwon with thirty thousand armored troops to help. (Samguk Sagi (History of the Three Kingdoms) 卷10 憲德王 11年)
Wang Bian and four others storm Wang Sui's banquet, shoot Zhang Dunshi dead, and set off a mutiny in Yizhou. (Zizhi Tongjian (Comprehensive Mirror) 資治通鑑 卷241)
Men of Yuezhou in Great Tang, Zhou Guanglun and Yan Shengze, came on a Silla ship and asked for news of the Tang; they were told that in the eleventh year of Yuanhe, Li Shidao of Yuanzhou (圓州) rebelled with 500,000 soldiers, and that the Son of Heaven sent the troops of the various circuits to suppress him but did not succeed. (Nihon Kōki (Later Chronicles of Japan) 日本後紀 卷27)
When the protector Li Xianggu lost the people's support through greed and oppression, Yang Qing killed him. (Đại Việt sử ký toàn thư 外紀卷之五 「己亥冬十月，都護李象古以貪縱苛刻」)
Yang Qing raids Annam, killing Protector-General Li Xianggu, his family, and over a thousand officials. (Zizhi Tongjian (Comprehensive Mirror) 資治通鑑 卷241)
West Asia (1)
Leo V receives an accusation of a plot by Michael II and questions him personally. Michael is sentenced to death (Skylitzes–Kedrenos, Synopsis of Histories part_09.txt L3752)
Western Europe (5)
Slaomir is brought to Aachen, accused, and since he cannot defend himself he is exiled; his kingdom is given to Ceadragus, son of Trasco (Royal Frankish Annals ARF a.819, Kurze 1895 p.150)
At the July assembly at Ingelheim the emperor sends the Italian army to Pannonia because of the rebellion of Riudewit, duke of Lower Pannonia, but they return without success. Riudewit, when his conditions as envoy are refused, incites neighboring tribes and prepares for war (Royal Frankish Annals ARF a.819, Kurze 1895 p.150)
Boruna, duke of Dalmatia and Liburnia, meets Riudewit coming to the Kulpa River, but in the first clash he is abandoned by Guduscan and survives thanks to his bodyguard. In December Riudewit invades Dalmatia and plunders, but after losing 3,000 men to Boruna's guerrilla raids he is driven out (Royal Frankish Annals ARF a.819, Kurze 1895 p.151)
Baldricus, who succeeded the duke of Friuli, enters the land of the Carantani and, with a small force, attacks Riudewit's army as it marches along the Drava River; he kills many and drives it out of the region (Royal Frankish Annals ARF a.819, Kurze 1895 p.151)
In the west, the emperor's son Pippin, by his father's order, enters Vasconia with an army, eliminates the rebels and pacifies the whole region (Royal Frankish Annals ARF a.819, Kurze 1895 p.152)