9 events the sources record for this year, grouped by region.
What happened
China (5)
Hun Jian met the Tibetan chancellor Shang Jiezan at Pingliang to form an alliance, but was ambushed by Tibetan soldiers and barely escaped; Cui Hanheng and some sixty others were captured. (Old Book of Tang (Jiu Tangshu), Annals 舊唐書 卷12 貞元3年)
Hun Jian held a covenant with the Tibetans at Pingliang, but the Tibetans seized the vice-envoy Cui Hanheng and killed the judge Han Yan (Pingliang Betrayal). (New Book of Tang (Xin Tangshu), Annals 新唐書 卷007 德宗·順宗·憲宗 貞元3年5月)
Hun Jian and Shang Jiezan meet on either side of an altar to swear an alliance; the Tibetans later betray the pact (Pingliang Covenant). (Zizhi Tongjian (Comprehensive Mirror) 資治通鑑 卷232)
Arichis, Duke of Benevento, on hearing of Charles's advance, sends his son Romuald to ask for peace, but he himself leads his army and camps at Capua. When the king moves first, he withdraws to Salernum, offers his two sons and promises obedience; the king halts the war and takes the younger son Grimoald as hostage (Royal Frankish Annals ARF(Einhard판) a.787, Kurze 1895 p.75)
Envoys of Tassilo, Duke of Bavaria, ask the pope to mediate a reconciliation, but when the king asks them to confirm their authority, the envoys say they have no power to answer. The pope declares he will excommunicate anyone who breaks a promise, and the matter comes to nothing. The king visits the tombs of the apostles and returns to Francia (Royal Frankish Annals ARF(Einhard판) a.787, Kurze 1895 p.77)
Western Europe (2)
In the reign of King Beorhtric, three ships of Northmen (Danes) came for the first time, and the men killed the reeve; these were the first Danish ships to come to England. (Anglo-Saxon Chronicle Giles/Ingram 1847 A.D. 787 항 (pg657.txt 줄 2328))
After the Worms assembly Charles divides his army into three for Bavaria: his son Pippin with the Italian army goes by the Trentina valley, the East Frankish and Saxon troops along the Danube, and Charles himself camps by the Lech near the suburb of Augusta. The besieged Tassilo comes, begs forgiveness and gives hostages (Royal Frankish Annals ARF(Einhard판) a.787, Kurze 1895 p.79)