What he did as the Junior Commander for Moo-Ryeong-Goon


Statue of
Chang Po-go in China

At that time, the main duty of Moo-Ryeong-Goon was to crack down on a rebel Pyeong-Ro-Goon(Ping-Lu-Jun in Chinese) against the Tang Dynasty, directed by the rebel leader Lee Sa-do, a Beon-Soo(Fan-Shou in Chinese, chief) of Pyeong-Ro-Chi-Cheong(Ping-Lu-Zi-Qing in Chinese, regional government). As a member of Moo-Ryeong-Goon, Chang Pogo participated in sweeping down on the rebel and was promoted to a junior commander in recognition of his distinguished accomplishment at battles.

Beon-Jin of Pyeong-Ro-Chi-Cheong was succeeded to Lee Jeong-ghee's family, migrant from Koguryo Kingdom in 765, and Lee became a Beon-Soo himself and ruled the Beon-Jin as a rebel. Until it was completely swept away in 819, the rebel were in power for 55 years across three generations--Lee Jeon-ghee(765-781), Lee Nap(781-792), Lee Sa-go(792-806) and Lee Sa-do(806~819)--by setting up their own 'Small Kingdom' at the Shan Tong Peninsula as their central quarters.

Once the rebel family of Lee Jeon-ghee possessed 15 provinces in Shan Tong Peninsula, controled an army of 10,000 soldiers, and became the largest Beon-Jin resisting against the ruling and interference of the Tang Dynasty in China. The reason they could emerge as the most powerful rebel in a short time, even threatening the Tang, was because they were commissioned to take over the task of ‘Hae-Un-Ap-Shilla-Balhae-Yang-Beon-Sa’(Hai-Yun-Ya-Xin-Luo-Bo-Hai-Liang-Fan-Shi in Chinese.

Buddhist temple Beop-Wha-Won in China


commissioner of diplomacy, public relations, and maritime trade for the Balhae and Shilla Kingdoms) from central government of the Tang Dynasty, and they could accumulate enormous wealth. In addition, it is presumed that they were also supported not only by the immigrants from Korean Peninsula who were economically active in the Shan Tong Peninsula, but also by economic power of Shilla people who came over to the Tang in China and took control of the region. However, the rebel of Pyeon-Ro-Goon led by the leader Lee was depressed by the attack from the central government of Tang Dynasty.

After the Tang Dynasty had conquered the revolt of Beon-Jin led by the leader Lee, they carried out a policy of reducing military force from 821, by 8 % each year to recover from the financial crisis inflicted by excessive military expenses having spent on overthrowing rebellion of Beon-Jin. Accordingly, the military force of Moo-Ryeon-Goon had to be reduced, and it is speculated that Chang Po-go was retired from Moo-Ryeon-Goon.

After retiring from the military service, Chang then unified Shilla people in the Tang in China who were living all over the continent along the seashore of the Shan Tong Peninsula and around the Great Canal regions. Especially, he constructed a Buddhist temple Beop-Wha-Won on Jeoksan(Chi-Shan in Chinese, red mountain) as a foundation to build up his power. He strived to bring Shilla people in unity by using not only the economic strength founded on trade and commercial activities, but also the religious influence of Buddhism. From his previous military experience at Moo-Ryeong-Goon, he established maritime order in East Asia and opened a bridgehead controlling the maritime trade among the three Asian countries - Shilla, Tang, and Japan.