In April 777 (Dingyou day), Tibetans invade Lizhou and Yazhou; Cui Ning, Jiedushi of Xichuan, defeats them. (Zizhi Tongjian (Comprehensive Mirror) 권225 777년 항)
Japan (2)
The Tang-bound envoys offer sacrifices to the heavenly and earthly deities at the foot of Mount Kasuga; because they could not cross last year due to storms, Vice-envoy Ono no Ishine performed the sacrifice again. (Shoku Nihongi (Continued Chronicles of Japan) 續日本紀 卷第34 「二月戊子。遣唐使拜天」)
Mutsu Province, exhausted after using soldiers from the whole country in April against the enemy of the two routes, asks for exemption from this year's tribute and last year's land tax; it is granted. (Shoku Nihongi (Continued Chronicles of Japan) 續日本紀 卷第34 「九月癸亥。陸奥國言。」)
Western Europe (1)
After Easter at Noviomagus, Charles goes to Saxony to hold an assembly at Paderborn. Saxon leaders come and submit, and many are baptized; but Widukind flees to Sigifrid, king of Denmark. From Spain the Saracen Ibn al-Arabi comes and surrenders (Royal Frankish Annals ARF(Einhard판) a.777, Kurze 1895 p.49)