Silla conquers Daegaya, the last of the Gaya states

Gaya was a league of small polities in the basin of the Nakdong River, known for its iron, which it exported to Baekje and to the Wa of Japan. In the early 6th century Silla grew strong under King Beopheung: the Samguk sagi dates its official adoption of Buddhism to 528, and in 532 the king of Geumgwan Gaya at modern Gimhae surrendered with his queen and three sons and was received into the Silla nobility. King Jinheung (reigned 540–576) turned on his ally Baekje: in 553 Silla seized lands in the Han River valley that the two kingdoms had just taken from Goguryeo, and in 554 King Seong of Baekje, attacking the fortress of Gwansan together with Gaya troops, was killed — the chronicle claims that 29,600 Baekje soldiers fell.

Daegaya, centred at modern Goryeong, had led the Gaya league since the late 5th century; its king Haji sent an embassy to the Southern Qi in 479. In the ninth month of 562, says the Samguk sagi, ‘Gaya rebelled’. The king sent Isabu with the young Sadaham as his deputy; Sadaham rode ahead with 5,000 horsemen, entered the Jeondan gate and raised a white banner, and the terrified city surrendered as soon as Isabu arrived. Sadaham was rewarded with land and 300 captives, whom he set free. The Nihon shoki records Silla’s destruction of ‘Mimana’ — a name it explains as covering ten Gaya polities — under the first month of 562, with a variant placing it in 560; the English article on Jinheung gives 561.

With Gaya, Silla gained the whole Nakdong basin. The Gaya nobility, including the royal house of Geumgwan, was absorbed into Silla’s bone-rank aristocracy — the 7th-century general Kim Yu-sin descended from it. In the 20th century Japanese imperialists cited the Nihon shoki’s picture of Mimana as a Yamato outpost to justify colonial rule in Korea; the English article on Gaya notes that there is no evidence to support this claim.