King Seong of Baekje

Seong was the twenty-sixth king of Baekje, one of the three kingdoms that shared the Korean peninsula in the sixth century, alongside Goguryeo in the north and Silla in the south-east. He came to the throne in 523 after the death of his father, King Muryeong, whose tomb in Gongju is one of the most famous archaeological discoveries in Korea.

Korea’s oldest surviving history, the Samguk sagi (1145), describes him as a man of outstanding intelligence who could make decisions, and says that the people of the country called him Seong, “the Sage”. Japanese chronicles call him Seongmyeong-wang, the “Sage and Bright King”.

Seong ruled from 523 to 554; the Samguk sagi counts his final year as the thirty-second year of his reign. His reign can broadly be discussed in two parts. In the first he rebuilt the kingdom at home, moving the capital and reorganising government. In the second he tried to restore Baekje’s old heartland on the Han River, an effort that ended with his death in battle in 554.

In 475 Goguryeo had captured Baekje’s first great capital, Hanseong, near modern Seoul, and killed its king. The survivors fled south to Ungjin (modern Gongju), a small town protected by hills and the Geum River. It was a good hiding place but a cramped capital.

In 538 Seong moved the court further down the Geum River to Sabi (modern Buyeo), where a broad plain gave room for a planned city and the river gave access to the Yellow Sea. A mountain fortress was built on Mount Buso above the river, and an outer earthen wall, the Naseong, protected the city on its landward side. Inside were palaces, government offices, residential districts laid out along a grid of roads, and Buddhist temples. At the site now called Jeongnimsa a five-storey stone pagoda still stands, but the temple’s founding date and the pagoda’s date are debated, and the name Jeongnimsa itself is known only from Goryeo-period roof tiles.

At the same time Seong renamed the kingdom Nambuyeo, “Southern Buyeo”. Buyeo was an ancient kingdom in Manchuria from which both Baekje’s and Goguryeo’s royal families claimed descent. By using this name Seong reminded everyone that Baekje’s kings came from a line as ancient and noble as Goguryeo’s.

Seong kept up close contact with the Liang dynasty, which ruled southern China from its capital Jiankang (modern Nanjing). Baekje envoys brought gifts and received titles from the Liang emperor. In 541, the Samguk sagi records, Seong asked for a specialist on the Confucian classics, commentaries on the Nirvana Sutra, craftsmen and painters, and the Liang court sent them.

Baekje passed much of this knowledge on to the Wa court in Japan. Seong sent a gilt-bronze Buddha image, banners and sutras, which Japanese tradition remembers as the official introduction of Buddhism to Japan. The Nihon shoki also records that Baekje sent specialists in shifts: in 554 a scholar of the Five Classics, monks, a scholar of the Book of Changes, a calendar expert, a doctor, herbalists and musicians arrived to replace those who had served before them.

These records show Baekje taking part in exchanges of religious texts, objects and specialist knowledge between the Liang court, the Korean peninsula and the Wa court. They do not mean that every transfer of architecture, writing, medicine or calendrical practice can be dated to Seong’s reign.

Historians see the move to Sabi as a planned political project rather than a flight. The Ungjin period had begun in chaos: after 475 several kings were murdered by powerful nobles, and the throne depended on aristocratic clans who had settled in the Gongju area. Seong’s father Muryeong restored stability; Seong used the new capital to reshape power. A new city meant new land, new offices and the chance to favour families who supported the king, notably the Sa (沙) clan associated with the Sabi region.

Korean historians attribute a series of reforms to this period. Central government was organised into twenty-two departments, twelve serving the palace and ten handling state affairs. Officials were ranked in a sixteen-grade system distinguished by the colour of their robes. The capital was divided into five districts (bu), and the provinces into five regions (bang), each with a fortress-based administration controlling commanderies below it.

Our knowledge of these institutions comes largely from Chinese histories of the Zhou and Sui dynasties, which describe Baekje as it was in the later sixth century, so it is not certain that every element was created under Seong. What is clear is that the Sabi period produced a more centralised monarchy, and that its planned capital, with its fortress, city wall and temples, became the model for the rest of Baekje’s history until 660.

Buddhism was part of this programme. Temples in the capital served as centres of learning and royal ritual. A tradition first attested in Yi Neunghwa’s 1918 history of Korean Buddhism says that the monk Gyeomik studied in India and brought Vinaya (monastic discipline) texts back to Baekje, where they were translated. Whether the date 526 refers to his departure or his return is unclear, and the reliability of the account is debated because no earlier source records it.

Liang was ruled for most of Seong’s reign by Emperor Wu (r. 502–549), a devout Buddhist who sponsored the first Chinese collection of the Buddhist canon and, in 527, 529 and again in 547, renounced the world and entered a monastery, returning to the throne only after great persuasion. Baekje’s interest in Liang was partly cultural and partly strategic: Liang was the great rival of the northern dynasties that bordered Goguryeo. In 524 the Liang emperor granted Seong the title of general and King of Baekje, confirming the recognition already given to Muryeong.

A rare picture of these contacts survives in the Portraits of Periodical Offering, a record of foreign envoys who came to Liang around 526–536, painted and annotated by Xiao Yi, a Liang prince who later became Emperor Yuan. Part of it is lost; the surviving copy preserves envoy pictures and notes for twelve countries, including Baekje, Persia, the Hephthalites of Central Asia, Kucha and Wa (the text transmitted under Wa combines material about Wa and the Dangchang state). The Baekje envoy, shown in a wide-sleeved robe and cap, is accompanied by a short text whose account of Baekje largely matches the Liang shu. For the Liang court, Baekje was one of many kingdoms whose visits displayed the emperor’s standing; for Baekje, relations with Jiankang gave access to Liang’s court, learning and Buddhist culture.

The relationship ended in tragedy. In 548 the general Hou Jing rebelled and besieged Jiankang, and Emperor Wu died in 549. The Samguk sagi relates that a Baekje embassy, unaware of the rebellion, arrived that year to find the palace in ruins, and wept outside the palace gate, moving passers-by to tears; Hou Jing then detained the envoys until his fall. Liang never recovered, and Baekje later turned to the Northern Qi, Chen and eventually Sui.

Since 433 Baekje and Silla had been allies against Goguryeo. In the 540s Goguryeo was weakened by a succession struggle, and in 548 Silla helped Baekje repel a Goguryeo attack on Doksan fortress. In 551 Seong led a joint offensive with Silla and Gaya: Baekje recovered the lower Han River basin, including its old capital region, while Silla under King Jinheung took the upper reaches.

The victory did not last. In 553 Silla turned on its ally, seized the lower Han basin and set up a new province there, Sinju. According to the Samguk sagi, a daughter of Seong was married to the Silla king in the same year, which suggests that diplomacy continued even as the alliance collapsed. For Silla, control of the Han valley meant direct access to the Yellow Sea and to China, a prize that would prove decisive in the next century.

In 554 Seong’s son, Prince Yeochang, led Baekje forces with Gaya contingents (and, according to the Nihon shoki, some Wa troops) against the Silla fortress of Gwansan, near modern Okcheon. After early successes, Silla reinforcements under Kim Muryeok arrived. Seong set out at night with only fifty foot soldiers and horsemen and was ambushed and killed at a place called Gucheon. The Samguk sagi says he was going to raid Silla; the Nihon shoki says he was going to comfort his son, who had been in the field for a long time. The Samguk sagi names the killer as Dodo, an officer from Samnyeonsan commandery, and says that four jwapyeong and 29,600 soldiers were killed. The Nihon shoki names the executioner as Kodo (苦都), a horse-keeping slave from a Silla village. A variant preserved in the Nihon shoki says that Silla kept Seong’s skull, returned his other bones to Baekje, and buried the skull beneath the steps of the North Hall of a Silla government office.

The defeat ended the Baekje–Silla alliance for good. For the next century Baekje and Silla fought almost continuously, until Silla, allied with the Tang empire, destroyed Baekje in 660.

Seong’s reign unfolded within a network of exchange across East Asia. His envoys travelled to the Liang court at Jiankang, where they sought specialists and Buddhist texts, while Baekje sent religious objects and skilled people to the Wa court in Japan. These contacts helped make Baekje an important route by which learning, religious practices and artistic techniques moved between southern China, Korea and Japan.

The Liang envoy scroll places Baekje within a wider diplomatic world that also included Persia and the states of Central Asia. It shows that the Liang court received envoys from very distant lands, but it does not show the routes or the speed by which particular goods and texts reached Baekje.

Much closer, Seong’s neighbours were also transforming themselves. In Silla, King Beopheung promulgated laws in 520 and annexed Geumgwan Gaya in 532, and King Jinheung (r. 540–576) expanded in every direction. In Kyushu, Iwai fought the Yamato court from 527 until his defeat in 528. In Japan the reign of Emperor Kinmei (traditionally 539–571) was the setting for the arrival of Baekje’s Buddhism, and in 588 construction of Asuka-dera began with the help of monks and specialists from Baekje.

Buddhist learning gives a closer view of these connections. In 541 Seong asked Liang for commentaries on the Nirvana Sutra, as well as teachers and artisans. Baekje also sent Buddhist images and scriptures to the Wa court, followed by specialists who could teach and work there. These documented exchanges link the religious and cultural history of the three courts more directly than events occurring elsewhere at the same time.

Seong’s son Chang, known as King Wideok, reigned for more than forty years after the disaster. Near the royal tombs at Neungsan-ri, just outside Sabi’s city wall, archaeologists found a temple site where, in 1993, the magnificent Gilt-bronze Incense Burner of Baekje was excavated. In 1995 a stone reliquary niche was found beneath the site of the temple’s wooden pagoda. Its twenty-character inscription (百濟昌王十三秊太歲在丁亥妹兄公主供養舍利) records that in the thirteenth year of King Chang, a jeonghae year (567), a princess referred to as 妹兄公主 offered relics. She is commonly identified as Wideok’s younger sister and therefore Seong’s daughter, but the inscription does not name Seong, and whose sister she was is not conclusively established. The inscription dates the relic offering rather than the founding of the whole temple, but most scholars date the temple to around 567 and see it as a royal establishment linked to the nearby tombs and to prayers for the dead King Seong.

The city Seong founded remained Baekje’s capital until 660. Its remains, including Busosanseong, the Naseong wall, Jeongnimsa and the Neungsan-ri tombs, are now part of the UNESCO World Heritage Site “Baekje Historic Areas” (2015), together with sites in Gongju and Iksan. The Baekje Cultural Festival held in Buyeo and Gongju celebrates this heritage.

In Japan Seong is remembered as the king of Baekje whose envoys presented a Buddha image and sutras to the Yamato court. Japanese reference works still describe this as the official transmission of Buddhism to Japan, while noting that immigrants had probably brought Buddhism earlier and that the year is disputed.

538 or 552? The year when Seong’s mission brought Buddhism to Japan is famously uncertain. The Nihon shoki (720) places it in the thirteenth year of Emperor Kinmei, corresponding to 552, and describes a court debate in which Soga no Iname supported the new faith while the Mononobe and Nakatomi opposed it. The Jōgū Shōtoku hōō teisetsu and the Gangōji garan engi preserve a tradition dating it to a wuwu (戊午) year corresponding to 538; their own dates of compilation and textual transmission are also debated. Many Japanese reference works treat 538 as the stronger date. Critics of 552 note that the Nihon shoki’s account borrows wording from the Golden Light Sutra and that 552 was reckoned as the first year of the “latter age of the Dharma”; but the 538 date has also been explained by a calendrical theory about wuwu years, so neither date has decisive support. Buddhism had probably reached Japan earlier through immigrant families from the peninsula. The question therefore involves both chronology and source criticism, and it shows how Korean and Japanese sources must be read together.

Gaya and the “Mimana” question. The Nihon shoki records meetings convened by Seong at Sabi in 541 and 544 with representatives of the Gaya states and envoys associated with Wa, which it calls conferences to “restore Mimana”. Pre-war Japanese historiography read these passages as proof of a Yamato colony in southern Korea (the “Mimana Nihonfu”). Japanese reference works now note that scholars are divided over whether such an office existed at all and that many reject the idea of Yamato colonial rule; one view sees the “Nihonfu” as a group of Wa officials stationed in Anra (Aragaya). The meetings also need to be seen from the side of the Gaya states: Anra and the other Gaya polities sought Baekje’s military support against Silla, while Baekje pursued its own interests, and the participants did not share the same aims. These passages do not by themselves demonstrate Yamato colonial rule.

Betrayal or strategy? Silla’s seizure of the lower Han basin in 553 is often described as a betrayal of Baekje. Its causes are debated: explanations include Silla’s strategic ambitions, a secret understanding between Goguryeo and Silla, and Baekje’s difficulty in consolidating control of the region. The final campaign also divided Baekje itself: the Nihon shoki says the elders warned Prince Yeochang against attacking Silla, and Korean historians see these elders as an aristocratic peace party whose voice grew after the defeat, so that power shifted from the throne towards the nobility.

The main written sources for Seong are the Baekje and Silla annals of the Samguk sagi, compiled in Goryeo in 1145; the Chinese dynastic histories of the Liang, Zhou and Sui; and the Nihon shoki. The Samguk sagi’s Baekje annals for his reign are brief and concentrate on diplomacy and war. Chinese histories supply titles and descriptions of institutions. The Nihon shoki contains by far the most detail about Baekje in the 540s and 550s, apparently drawing on lost Baekje histories such as the Baekje bongi, but embeds this material in an imperial ideology that presents Baekje as a tributary of Yamato.

Archaeology now provides an independent check. Excavations at Busosanseong, the Naseong wall, Jeongnimsa, the Gwanbuk-ri area (a candidate for the royal palace) and the Neungsan-ri temple and tombs have clarified the plan and dating of Sabi. Wooden tablets (mokgan) from Sabi-period sites reveal administrative practices, and the 567 reliquary inscription is a contemporary text that confirms the reign of King Chang. Archaeological evidence complements the written accounts of cultural exchange in the later Baekje period.

Where Seong himself was buried is uncertain. The tombs at Neungsan-ri are royal stone-chamber tombs of the Sabi period, and one of them is often proposed as his, but no inscription has confirmed this. Unlike his father Muryeong, whose tomb was identified by its epitaph, Seong remains known mainly through what others wrote about him.