If you ask me what is the hardest place in history to conquer? I would definitely say Goguryeo and Goryeo.
Although Goguryeo and Goryeo dynasty are two concepts. Goguryeo was an ethnic minority regime established by the Buyeo people in ancient China in the northeast, originating in Jilin and later entering the Korean Peninsula. Goryeo was a regime established by the ancient Korean Wang Jian, which was separated from the Silla State and originated in the southern part of the Korean Peninsula.
However, Goguryeo and the Goryeo Dynasty were very close in territory and history, and they were difficult places to conquer. Thinking that in order to destroy Goguryeo that year, the Sui Emperor did not hesitate to destroy the country and also wanted to conquer Goguryeo three times, and then Li Shimin also launched an unprecedented attack on Goguryeo, but with little success, until the time of Li Zhi, Goguryeo was completely subjugated.
The same was true of the later Goryeo Dynasty. In order to completely destroy the Goryeo Dynasty, the Mongol army sent troops nine times before it was completely conquered.
The Mongol-Goryeo wars took place mainly between 1231 and 1273 AD. Of course, the story has to start from the beginning.
In 918, Wang Jian founded the Goryeo Dynasty and in 935 destroyed Silla to unify the Korean Peninsula. Subsequently, the Goryeo Dynasty passed through the middle and late Tang Dynasty, the Five Dynasties and Ten Kingdoms and the Song Dynasty. Until 1216 AD, after a failed rebellion by a Khitan army originally attached to the Mongols, it entered the territory of Goryeo and occupied the eastern part of the Goryeo River, seeking the independence of the "Black Khitan", and using it as a stronghold to burn and loot everywhere.
In 1218, when the Mongol general Hajin commanded a large army to pursue the Khitan rebels into Goryeo, the King of Goryeo sent the general Zhao Chong to lead the army to assist and provide food and grass to the Mongol army. Under the joint efforts of the Mongol pursuers and Goryeo, the Khitan rebel army that had sneaked into Goryeo was completely wiped out, and then Mongolia and Goryeo signed a treaty of friendship that "the two countries are brothers, and all future generations will never forget today".
Although it was a treaty of friendship, it was not actually "friendly" because Goryeo paid tribute to Mongolia every year. Mongolia is even more open for lions, asking for a lot every time, from fur and mountain treasures to pen, ink and paper. The goryeo state was small and poor, and there were not many products, so it could not withstand this repeated demand. As a result, hostility toward Mongolia gradually warmed up and contradictions intensified.
In 1225, when it was time for Goryeo to pay tribute to the Mongols, the Mongols sent emissaries as usual, but unlike usual, this time Goryeo refused the Mongol request and even killed the Mongol emissaries on their way back.
This caused the anger of the Mongols, but at that time the Mongol army was marching westward, and the Great Khan Genghis Khan had died, so the Mongol army did not immediately retaliate against Goryeo. It was not until 1231 AD, after the Great Khan of Wokoutai ascended the throne, that in August of that year, on the pretext that Goryeo killed the emissaries, he sent Sarita to lead a Large Mongol army to attack Goryeo.
This was the first time that the Mongol army sent an army to fight against Goryeo. The Mongol army went out for the first time and won a complete victory, all the way to the middle of the Korean Peninsula, capturing more than forty cities, the Goryeo general Hong Fuyuan surrendered, and the Goryeo king, who could not resist, finally surrendered. Subsequently, Sarita set up capital, prefecture, and county in Goryeo and ordered 72 people to guard Daru Huachi, and the army withdrew from Goryeo.
The following year, the Goryeo kings rebelled, killing 72 of the Daru Huachi garrison at Kaesong, and in order to avoid retaliation from the Mongols, the Goryeo kings migrated to Ganghwa Island, which is now Jeju Island.
The Great Khan of Wokoutai, who knew the news, was furious and once again sent Sarita to lead his division to conquer Goryeo. This was the second Mongol expedition to the Goryeo Dynasty.
This time, the Mongol army fought all the way to the southern tip of the peninsula, but could not capture Ganghwa Island, and the Mongol commander Salita was also killed by random arrows, and the army had to retreat. Although the king of Later Goryeo sent envoys to plead guilty, he still refused to submit to the Mongols.
The Great Khan of Wokoutai told the King of Goryeo to repent, but the King of Goryeo occupied Ganghwa Island and refused to repent, but instead sent troops to attack Xijing and other places that had been annexed to the Mongols, and robbed the home of the general Hong Fuyuan.
The enraged Wokoutai Khan decided to go on a third crusade against Goryeo. Seeing the Mongol army, the king of Goryeo once again used a delaying tactic, announced his surrender, and took the Goryeo royal family as a hostage. So the Mongols suspended their attack. But then they found out that it was a fake prince who had been sent over.
The Great Khan of Wokoutai was once again furious and attacked Goryeo for the fourth time. In 1240, the Mongol army conquered Changzhou and Shuozhou, forcing the king of Goryeo to take his own son as his son, and Goryeo submitted to the Mongols and continued to pay tribute
After the death of the Great Khan of Wokoutai, the Goryeo Dynasty repented and refused to pay tribute. In 1247 AD, the Mongols sent an army to Goryeo for the fifth time, asking the Goryeo royal family to move out of Ganghwa Island and Shizi into hostage, but the Mongol Great Khan Guiyu died suddenly, and the Mongols had to withdraw their troops, and the fifth time they returned without success.
In 1251, Möngke Khan succeeded to the throne. As soon as the successor Möngke Khan took office, he demanded that the Goryeo royal family immediately move out of Ganghwa Island and move to Mongolia as hostages.
However, this move was rejected by Goryeo, and the Mongol army went to Goryeo for the sixth time. Reluctantly, Gojong, the king of Goryeo, agreed to move out of Ganghwa Andewa and hand over Son Anqing to the Mongols as hostages, who subsequently withdrew.
However, Goryeo made a verbal promise and did not take any actual action, and Möngke Khan was very unhappy and launched two devastating attacks on Goryeo in succession, the seventh and eighth, leading to a palace coup in Goryeo. Choe Shi, the powerful minister who advocated abandoning Lubao Island, was killed, and then Goryeo went out to land and surrendered to the Mongols.
In 1259, Mongolia and Goryeo reached a settlement agreement, the Mongol army withdrew from Goryeo, the Goryeo court moved out of Ganghwa Island to move to land, and sent princes into Mongolia, Goryeo became a vassal state of Mongolia, and the state of war between the two countries ended.
In the spring of 1260, in the first year of the reign of Kublai Khan, the ancestor of the Yuan Dynasty, King Gojong of Goryeo died. So Kublai Khan sent troops to escort the Goryeo prince back to the throne, for the sake of Emperor Wonjong of Goryeo.
Since Goryeo Wonjong had always been pro-Yuan, it caused dissatisfaction among the anti-Yuan faction in Goryeo who advocated the abolition of Wonjong. Kublai Khan decided to send troops to Goryeo to help Emperor Yuanzong restore the throne. This time the Mongol army sent troops to Goryeo for the ninth time. The war ended with the fall of the Fifty Cities in the North under the command of Goryeo Saikyo.
Subsequently, Goryeo Emperor Wonjong moved the capital from Ganghwa Island back to Kaesong, declaring his submission to the Mongols inside and outside. The following year, Kublai Khan assigned the Western Capital of Goryeo to Dongning Province in Liaoyang Province of the Yuan Dynasty, and in 1276, he changed Dongning Province to Dongning Road, which actually included the area under the jurisdiction of Dongning Road into the territory of the Yuan Dynasty.
Later, Goryeo and Mongols intermarried for generations, and Kublai Khan also set up Daru Huachi in Goryeo to oversee the Goryeo king. In short, in order to completely destroy the Goryeo Dynasty, the three great khans of Wokoutai, Möngke and Kublai Khan sent troops nine times to completely conquer it. You say that Goryeo is not difficult to conquer! It's too hard.