[5] In the 1960s, the North Korean scholar Pak Se-yong argued that Balhae was "a part of Korean history", "a state founded by people of Koguryŏ", and that its territory was "composed of most of the former territory of Koguryŏ and an expansive, newly acquired portion".

[3] According to this narrative, Goryeo was the first unification of Korea, since Balhae co-existed with Unified Silla while occupying former Goguryeo territory north of the Korean peninsula.

In 1981 a South Korean scholar called the Northern–Southern Dynasties an "interesting new interpretation",[7] and as late as 1990 there was still no consensus.

Unified Silla carried on the maritime prowess of Baekje, which acted like the Phoenicia of medieval East Asia,[13] and during the 8th and 9th centuries dominated the seas of East Asia and the trade between China, Korea and Japan, most notably during the time of Jang Bogo; in addition, Silla people made overseas communities in China on the Shandong Peninsula and the mouth of the Yangtze River.

[14][15][16][17] Unified Silla was a prosperous and wealthy country,[18] and its metropolitan capital of Gyeongju[19] was the fourth largest city in the world.

Its name was another transcribed version of Mohe, a Tungus Tribe speaking a language like Manchurian and Sibe.

It was founded in the northern part of former lands of Goguryeo by Dae Joyeong, a former Goguryeo general[35][36] or chief of Sumo Mohe,[37][38][39] after defeating the military of central government of Tang dynasty at the Battle of Tianmenling.

Balhae controlled the northern areas of the Korean Peninsula, much of Manchuria, and expanded into present-day Russian Maritime Province.