By the 4th century BCE, Gojoseon had reached its height of power, pushing its way north into Manchuria, thanks to a new super weapon that was about to shake the ancient world: iron. Although still not completely developed, it allowed not only new modes of fighting and improved weapons, but also changed society at home. The rulers of Gojoseon adopted the title of “king” which proved their political power at the time. The Chinese state of Yan got fed up with what they perceived to be Gojoseon’s arrogance, and they attacked, greatly weakening the country. It would take a few hundred years, but in the 2nd century BCE, King Ugeo found himself ruling a country that was regaining its lost power, thanks to the work of his grandfather and old enemies.
Although Yan managed to defeat Gojoseon, the state itself was part of a time of great upheval, and was eventually absorbed into the greater empire of Qin (where the word ‘China’ comes from). Great Empire that it was, it didn’t manage to hold power for more than a few decades, when it was overthrown by the Han. All this political turmoil meant that a lot of people were caught in intrigue, and scores of refugees were escaping the new Han Empire.
One such person observing the state of affairs was Gojoseon’s King Jun. He accepted a lot of these refugees into his kingdom as his subjects. He sent a general, Wiman, to fortify the borders against all this chaos. Wiman is said to have been a refugee from Yan, who had assimilated into Gojoseon, adopting the traditional dresses and top-knot style, but like most biographies of this era it is up for debate. Either way, Wiman’s power base of refugees had given him the opportunity to overthrow King Jun, who escaped at the southernmost parts of the Korean peninsula to a people called the Jin (not to be confused with Jin of China…or Jin of China again…or Jin of the Jurchens…or Later Jin of the Manchurians…Jin was an awfully popular name for a country). King Jun would have an important role to play in that country, but more on that later. For now, Wiman was in charge.
With his military capabilities and economic strength, Wiman invaded the tribes surrounding Gojoseon and began expanding right by the Han borders. By now iron became a mainstay in his power. The relationship between Gojoseon and Han was tense, to say the least, as the two did not enjoy being so close to one another. And this was the situation that Ugeo inherited when he became king.
Things continued on thier way, Wiman and his son ruled without much incidence, and then when King Ugeo reached the throne, his kingdom had grown so powerful that it blocked other tribes and countries from being able to trade with the Han Empire. The Emperor of Han, Wu, tried to find a way to appease this bothersome country, and sent an envoy called She-He to request an audience with King Ugeo. This audience would not happen, and She-He was escorted back to Han. He did go back, but not before killing his Gojoseon escort in frustration, a move that is generally frowned upon by most schools of diplomacy.
Emperor Wu showed similar lack of diplomatic skills when Gojoseon demanded that She-He be brought to justice. Instead, Wu gave She-He rewards and titles. This was too much, and King Ugeo would show just how he felt about this by sending troops to go and kill She-He. The situation had reached its end point, and the conflict between Han and Gojoseon, many decades in the making, had begun.
Emperor Wu’s plan was to overwhelm the Gojoseon forces from land and sea. 50,000 sailed towards the country, while another group were advancing through land. They were both led by two of Emperor Wu’s generals with a similar objective: to capture the Gojoseon capital of Wanggeom. King Ugeo sent his army to the mountains to stop the troops from reaching the country. Meanwhile, the ships had landed, and the troops marched towards the capital. They were quickly repelled and admiral fled. The first wave of attacks had failed.
The two countries attempted peace negotiations, but looking back at the She-He incident, its obvious that diplomacy was not the strong point of these two monarchs. The battle resumed, and Wanggeom was now under siege. Frustrated by the lack of progress, Emperor Wu sent another general to take command of the army and attacks became more powerful and more concentrated. King Ugeo and his soldiers were able to repel attack after attack, but things were already starting to crumble- politically speaking- on the inside. Some ministers in court suggested that surrender was the best option. The strain of a siege, and such a long war, no doubt had some terrible consequences to the people and the land. What’s more, Emperor Wu was a capable military leader who had expanded his empire and fought successfully many wars already. How much longer could they hold out?
Four ministers presented their case for giving up.Perhaps it was due to stubbornness, perhaps because he thought things had gone too far to turn back now, or perhaps because he believed they actually had a chance of winning the battle, King Ugeo refused surrender. The attacks on Wanggeom the king managed to fend off, but he ignored this new pro-Han faction at his peril. Because in 108 BCE, one of the pro-Han ministers had defected, and went back to Gojoseon in order to have the king assassinated.
King Ugeo was dead, but his ambitions lingered on. A minister named Seong gi took controls and continued the war. It was already too late by then. Seonggi was also assassinated and Wanggeom, the city named after Dangun Wanggeom, had fallen. In the year 108 BCE, Gojoseon was no more.
Emperor Wu did not invade the country. Instead, he set up four commanderies around the former lands of Gojoseon. These commanderies were major towns run by Han ministers who would report back tot he Emperor and keep an eye out on the activities of over tribes. One of the reasons they were set up was to make sure no other tribe or city would grow too powerful. They would eventually fail. But for now, the commanderies were part of the Korean peninsula, something the people of the land greatly resented.
With Gojoseon gone, other kingdoms in the peninsula were about to flourish. Jin, the country that housed King Jun after he escaped Wiman, had grown considerable in economic power, and transformed into the Samhan (Three Hans): Mahan, Jinhan and Byeohan. There was also the kingdom of Buyeo to the north as well as various other tribes and city states around these bigger political entities.
So with the four Han Commanderies, the Samhan, Buyeo, Okje and Ye in place, the land was ripe and ready for the next phase of Korean history known as the Three Kingdoms Period.