Gwanggaeto the Great

Gwanggaeto, the nineteenth king of Goguryeo, reigned from 391 to 412 and in barely two decades made his kingdom the dominant power of north-east Asia. He humbled the rival Korean kingdom of Baekje, made Silla a dependent ally, drove back the Later Yan state from Liaodong and raided deep into Manchuria. His posthumous name means roughly "broad expander of territory", and he is one of only two Korean monarchs commonly called "the Great". Much of what is known of him comes from a huge stone monument whose wording is still disputed.

He was born in 374 at Gungnae, the Goguryeo capital on the Yalu River. Three years earlier Baekje had crushed Goguryeo, killed its king Gogukwon and sacked Pyongyang. Gogukwon's successor Sosurim made peace with Baekje, spread Buddhism and reorganised the army, and the next king, Gogukyang, Gwanggaeto's father, began to fight back. Gwanggaeto succeeded him in 391. He adopted the era name Yeongnak, "eternal rejoicing", and the title Taewang, "supreme king", claiming equal standing with the emperors of China.

In 392 the young king invaded Baekje with a reported 40,000 men and took ten walled towns. Baekje's King Asin struck back in 393 and 394 and was beaten each time. In 396 Gwanggaeto attacked the Baekje capital, Wiryeseong on the Han River near modern Seoul, by land and by river. Asin submitted, handing over a prince and ten ministers as hostages.

While fighting in the south, Gwanggaeto also campaigned against the Khitan on the Liao River in 395 and against the Sushen people of the north-east in 398. The Xianbei state of Later Yan attacked in 400, but he drove it off, took one of its fortresses in 402 and beat back further attacks in 405 and 406, winning control of the Liaodong peninsula, which Goguryeo would hold until the seventh century. In 410 he attacked Eastern Buyeo.

Around 399 or 400 Silla, in the south-east of the peninsula, appealed for help against an invasion by Baekje, the Gaya states and the Wa, warriors from the Japanese islands. Gwanggaeto is said to have sent 50,000 troops, who routed the invaders; Silla became a client of Goguryeo, and Gaya never recovered. In 402 he sent home a Silla prince held as a hostage and set him on the Silla throne, and in 404 his forces defeated a Wa attack on his southern frontier. He died of an unknown illness in 412, aged about 38, and was succeeded by his son Jangsu, who reigned for 79 years.

In 414 Jangsu set up a granite stele about 6.4 metres tall near his father's tomb at Ji'an, in what is now China, inscribed with some 1,800 Chinese characters recounting Goguryeo's founding myth and Gwanggaeto's campaigns. Rediscovered around 1876, it was first studied in detail by Japanese scholars using a copy obtained in 1883 by an army officer. One damaged sentence about the year 391 has caused lasting controversy. The traditional Japanese reading says the Wa crossed the sea and made Baekje and Silla their subjects, a reading that early Japanese scholars took as evidence of a strong Wa state. Many Korean scholars, from Chŏng In-bo in 1955 onwards, read Goguryeo as the actor, and others note that "Wa" may not mean a Japanese state at all. In 1972 the scholar Lee Jin-hui claimed the Japanese army had deliberately altered the inscription, but Chinese researchers, including Xu Jianxin, who found a rubbing made before 1881, concluded there was no evidence of tampering.

Koreans regard Gwanggaeto as one of the greatest heroes of their history and a potent national symbol, and South Korea's navy has named a class of destroyers after him.

Our 400 map shows Goguryeo near its peak under Gwanggaeto, stretching across today's North Korea and north-eastern China, beside Baekje and Silla in the south of the peninsula and the islands of Japan.