Editing Balhae (section)

===Conflict with Mohe tribes and Silla===
The bilateral relationship between the Tang and Balhae grew friendlier. From 766 to 779, 25 missions from Balhae paid respect to Daizong. By the end of Heummu's reign in 793, princes from Balhae's royal family were serving as guards at the court of [[Emperor Dezong of Tang]] of their own volition. Peace with the Tang allowed Balhae to further expand its territory. After the death of Heummu, who was [[posthumous name|posthumously known]] as [[Mun of Balhae]] (Wen, r. 737–793), Balhae experienced a succession crisis. As a result, Balhae lost territory and bordering Mohe tribes rebelled. Both the reigns of [[Seon of Balhae]] (Xuan, r. 818–830) and [[Dae Ijin]] (Da Yizhen, r. 830–857) saw intrusions by Mohe tribes.{{sfn|Kim|2011|p=286}} Seon annexed the Yuexi Mohe and other tribes along the Amur valley in the north.{{sfn|Wang|2013|p=94}} In 818-820, he also invaded Liaodong and parts of Silla on Balhae's southern border.{{sfn|Shin|2014|p=66}} In 826, Silla mobilized tens of thousands of people to fortify the border with Balhae.{{sfn|Kim|2011a|p=354}} In the middle of the 9th century, Balhae completed its local administrative system, which was composed of five capitals, 15 prefectures and 62 counties.{{sfn|Kim|2011|p=286}}