The Tang-Silla Alliance
Silla now made the decisive move. The Silla crown prince, Kim Chunchu (later to be King Muyol, r. 654–661), personally visited Chang’an, the Tang capital, and presented a proposal to the emperor: If China would first aid Silla in battles against Paekche, then Silla would assist China in a combined attack on Koguryo.
China accepted the alliance. In 660 China sent its naval forces across the Yellow Sea, and Silla forces poured over the mountains, trapping Paekche soldiers between them. Paekche fell the same year. Just before its fall Paekche called on its ally Japan for aid. However, Japan was not in a position to respond.
With Paekche conquered by the combined forces of Tang and Silla, the alliance turned its attention to Koguryo. The stage was set for what should have been one of the greatest battles in history. Mighty Koguryo, which had successfully fought off six major invasions from China and had contributed to the fall of the Sui court, would now have to face enemies on two sides. Would Koguryo withstand the assault? In anticipation of a difficult battle, Silla forces marched north as Tang forces marched east.
However, during the relative peace that ensued when Tang focused its attention on Paekche, Koguryo had turned on itself. Dissension within the ruling elite on how to face their enemies led to a divisive palace coup in 666.
Forces loyal to the old king remained in control of some areas, and the country split. When the forces of Tang and Silla marched in, they discovered that the anticipated great battle was not to be.
The Koguryo forces were so overwhelmed and divided that hardly an arrow flew before the Koguryo kingdom fell in 668. Many soldiers fled and later became part of a new kingdom that formed on the far borders of Silla and Tang called Parhae (Pohai in Chinese) (Ki-ho Song 1999, 104).
Except for the most remote eastern section where the Parhae king-dom was later established, most of the Koguryo territory fell to the con-quering allies. The victors then proceeded to quarrel with each other. The fighting between the Tang and Silla ended fairly quickly, however, in favor of a diplomatic settlement in 676.
The Tributary System
Under the terms of their treaty, Silla became a part of the Tang tributary system. The Chinese system of demanding tribute was very different from that of other empires. Typically in history, a conquering empire exacting tribute from a subordinate state would demand as much as possible, often impoverishing the conquered people.
Sometimes the subordinated people would provide slaves or court women for the empire. This was not the case with China. Although it fluctuated in its generosity, often showing more exploitative trends at the beginning of a dynastic period, the Chinese court generally made modest demands for tribute.
When the tribute was delivered, the Chinese court benevolently responded by giving gifts in return. At times the Korean court would send tribute missions when it was not required because of the economic benefit to Korea.
The side trade, called “tribute trade,” that accompanied the missions was often beneficial to the diplomats themselves, and as a result, Korean diplomats pushed for any good reason to send a tribute mission to China. This system began with the Tang and Silla and continued during most of the dynasties to follow.
In the early years of the Silla-Tang relationship, recent warfare marred the relationship. As time went by, however, a peaceful and prosperous tributary relationship took root. Silla did not control the entire peninsula.
Tang, by right of its role in the conquest of Koguryo, demanded the northern third of the Korean Peninsula. For a time Tang even maintained military bases in former Paekche territory. Eventually, the Tang forces left Silla territory and retreated to the line on the northern third of the peninsula, where they had some problems with the Parhae.
As time passed the Chinese court took on a “big brother” attitude, and Korea took great pride in its “little brother” role, especially as acceptance of Confucianism grew. One of the five basic relationships of Confucianism is the relationship between older and younger, and that relationship is often cast in terms of brothers. Korea, proud of its younger brother status, considered itself a loyal (another Confucian virtue) member of the Chinese realm.