Unified Silla

The people of the Unified Silla period considered themselves to be of a kingdom of unified Koreans, which they called 三韓一統 (Modern Hangul: 삼한일통, Samhan-iltong), meaning the unity of three kingdoms (the three kingdoms being Silla, Goguryeo, and Baekje). The term was used by general Kim Yu-sin, credited with leading many of the military campaigns to unify the Korean peninsula under Silla, in a letter he wrote to King Munmu as he lay dying. King Munmu is considered to have been the first ruler of the Unified Silla period, and subsequent kings continued to hold the perception of a unified Silla, as evidenced by King Sinmun's installment of "nine counties" (九州) and "nine legions" (九書堂). In the ancient Sinosphere, the number nine connoted great things, and ancient China was composed of nine counties as well, so the term 九州 was used as a synonym for the entirety of China, as well as for "all under heaven" (天下). In addition, Silla gave noble ranks to the nobles of Goguryeo and Baekje as a token of unification.^[4]

North Korean historians criticize the idea of "Unified Silla" as from their perspective, Goryeo was the first state to unify the Korean people as Silla failed to conquer parts of Goguryeo and Balhae in the northeast of the Korean peninsula.^[5][6] Because of this, North Korean historians use the term "Late Silla" (후기신라) where South Korean historians would use "Unified Silla" or "Greater Silla".^[7]

In 660, King Munmu ordered his armies to attack Baekje. General Kim Yu-sin, aided by Tang forces, defeated General Gyebaek and conquered Baekje. In 661, he moved on Goguryeo but was repelled. Silla then fought against the Tang dynasty for nearly a decade.^[8]

During its heyday, the country contested with Balhae, a Goguryeo–Mohe kingdom, to the north for supremacy in the region. Throughout its existence, Unified Silla was plagued by intrigue and political turmoil in its newly conquered northern territory, caused by the rebel groups and factions in Baekje and Goguryeo, which eventually led to the Later Three Kingdoms period in the late 9th century.

Gyeongju remained the capital of Silla throughout the whole existence of the dynasty, which demonstrates the power of the governmental system employed in Silla. By using the “Bone Clan Class” system, a small group of powerful people (the 'bone clan') was able to rule over a large number of subjects. To maintain this rule over a large number of people for an extensive period of time, it was important for the government to keep the unity of the bone-rank system and hold the governed subjects in a low social status.^[9]

Despite its political instability, Unified Silla was a prosperous country,^[10] and its metropolitan capital of Seorabeol (present-day Gyeongju)^[11] was the fourth-largest city in the world at the time.^{[12][13][14][15]} Through close ties maintained with the Tang dynasty, Buddhism and Confucianism became the principal philosophical ideologies of the elite as well as the mainstays of the period's architecture and fine arts. Its last king, Gyeongsun, ruled over the state in name only and submitted to Wang Geon of the emerging Goryeo in 935, bringing the Silla dynasty to an end.

Unified Silla carried on the maritime prowess of Baekje, which has been likened to the "Phoenicia of medieval East Asia",^[16] 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 Chang Pogo; in addition, Silla people made overseas communities in China on the Shandong Peninsula and the mouth of the Yangtze River.^{[17][18][19][20]}

Unified Silla was a golden age of art and culture,^{[21][22][23][24]} as evidenced by the Hwangnyongsa, Seokguram, and Emille Bell. Buddhism flourished during this time, and many Korean Buddhists gained great fame among Chinese Buddhists^[25] and contributed to Chinese Buddhism,^[26] including: Woncheuk, Wonhyo, Uisang, Musang,^{[27][28][29][30]} and Kim Gyo-gak, a Silla prince whose influence made Mount Jiuhua one of the Four Sacred Mountains of Chinese Buddhism.^{[31][32][33][34][35]}

Unified Silla and the Tang maintained close ties. This was evidenced by the continual importation of Chinese culture. Many Korean monks went to China to learn about Buddhism. The monk Hyecho went to India to study Buddhism and wrote an account of his travels.^[36] Different new sects of Buddhism were introduced by these traveling monks who had studied abroad such as Seon and Pure Land Buddhism.^[36] A small Muslim presence also existed during this time.^[37][38]

Unified Silla conducted a census of all towns' size and population, as well as horses, cows and special products and recorded the data in Minjeongmunseo (민정문서). The reporting was done by the leader of each town.^[39]

A national Confucian college was established in 682 and around 750 it was renamed the National Confucian University.^[36] The university was restricted to the elite aristocracy. However, in Silla society, because the bone-rank system was used for the election of officials rather than the imperial examination process that was used in Confucianism, the National Confucian University did not have great appeal to the nobility class of Silla.^[40]

Silla was very scientifically and technologically advanced for the time. There was an emphasis put on astrology especially as it was closely tied to agriculture. This allowed them to accurately record events such as solar eclipses and lunar eclipses.^[41]

• History of Korea