In 1271, Kublai Khan established the Yuan Dynasty, becoming its first emperor, historically known as Emperor Shizu of Yuan. Kublai Khan spent his life on horseback, and his greatest achievement was founding the Yuan Dynasty and further unifying all of China.
In his youth, Kublai Khan harbored great ambitions, vowing to "achieve great deeds under heaven." He was deeply interested in Han Chinese culture, maintained close relationships with many learned Han scholars within the Mongol realm, and frequently sought their guidance on Confucian teachings.
In 1251, Kublai's brother Möngke inherited the Khan's throne. Knowing that his young and capable brother had always been particularly fond of Han Chinese culture, Möngke simply ordered him to govern all the Han people living south of the Gobi Desert. After Kublai took up his post in the southern desert region, he immediately set about tightening military discipline, opening up farmland for cultivation, promoting Confucian scholars, and rectifying official governance. Soon, he had managed the region so well that his army was strong and his horses robust, providing a powerful foundation for his later bid for the Khan's throne.
Möngke reigned for nine years and ultimately died in battle while leading an attack on the Diaoyu Fortress in Sichuan. At that time, Kublai was under orders to assault the Song Dynasty's Ezhou city; upon hearing this news, he realized that his brothers were surely already locked in fierce conflict over the title of Great Khan, and if he did not hurry back, he feared he would have no chance to compete with them.
The following year, Kublai and his brother Ariq Böke declared themselves khans at Kaiping and Karakorum respectively, becoming bitter rivals for the throne.
Four years later, Kublai defeated Ariq Böke and seized the title of Great Khan, then moved the capital to Yanjing, renaming it Dadu. After officially becoming the Mongol Great Khan, Kublai began to subdue the various forces within the Mongol Empire that refused to obey the central khanate's rule. Among these, the most critical was the elimination of the Ögedei Khanate established by Kaidu, a descendant of Ögedei. As a descendant of Tolui, Kublai's conflict with Kaidu could be traced back to their ancestors, Tolui and Ögedei.
Both Ögedei and Tolui were sons of Genghis Khan. After Genghis Khan's death, his third son Ögedei succeeded to the throne, but according to Mongol custom, the youngest son Tolui took control of the military power of the Mongol Empire, which planted the fuse for Tolui's later fate.
After Ögedei became the Great Khan of the Mongols, he was deeply wary of his younger brother Tolui, who held military power. Tolui had led armies on campaigns year after year, making great contributions to the expansion of the Mongol Empire, but he later died of illness in the military camp at the age of forty. However, there is also a claim that he was poisoned to death by his elder brother Ögedei.
After Ögedei's death, the power of the Mongol Empire fell into the hands of Tolui's descendants. Kaidu, a grandson of Ögedei, consistently sided with Ariq Böke during the struggle for the khaganate between Kublai and Ariq Böke. In 1268, Kaidu established the Ögedei Khanate on the former fiefs of Ögedei and his eldest son Güyük, proclaimed himself khan, and openly opposed Kublai.
Kublai Khan sent his own son, Nomukhan, to lead an army to attack Kaidu, but during the march, Nomukhan was betrayed by his subordinates and taken captive. The rebellious troops then defected to Kaidu, greatly strengthening his forces, and the following year, Kaidu launched an offensive against Kublai Khan.
Kublai Khan sent his trusted general Bayan to defeat the rebel forces at the Orkhon River. The rebels fell into internal strife and were unable to cope, and Nomukhan was also returned to Kublai's army. Under these circumstances, only Kaidu continued to fight, firmly holding onto Central Asia, standing in stark opposition to Kublai's occupied East Asia.
Nine years later, Kaidu allied with Mongol prince Nayan and other royal nobles to rise again, jointly opposing Kublai Khan's rule. The situation was critical, and Kublai Khan made a decisive move, leading a large army with General Yushu Timur to attack Nayan's forces. At the same time, Kublai Khan ordered Bayan to go to Karakorum to block Kaidu's army from invading the Yuan Dynasty. As a result, Nayan was defeated and captured, then executed by Kublai Khan. Kaidu's rebellion ultimately ended in failure once again, and he retreated to Central Asia. Kublai Khan naturally would not let this slide; four years later, he successively sent General Bayan and his grandson Temür to lead expeditions against Kaidu. Unfortunately, in early the following year, before the Yuan army could defeat Kaidu's forces, Kublai Khan passed away in 1294. It was not until 1309 that Kaidu's faction was finally destroyed by Kublai Khan's descendants.
After formally ascending to the Khan's throne and initially stabilizing the domestic situation, Kublai launched another attack on the Southern Song Dynasty. At that time, Emperor Lizong, who was on the throne of the Southern Song, was weak and incompetent, and his successor, Emperor Gong of Song, was young and ignorant, leaving the court completely under the control of the treacherous minister Jia Sidao. Had it not been for the unwillingness of the Southern Song soldiers and civilians to become subjugated people and their persistent resistance against the Mongol army, the Southern Song would likely have been destroyed by Kublai much earlier. After more than a decade of warfare, in early 1276, the Southern Song capital of Lin'an was finally captured, and the young Emperor Gong of Song, along with a large number of imperial clan members and court officials, were taken prisoner.
In 1271, prior to this, Kublai Khan had formally established the Yuan Dynasty with its capital at Dadu (present-day Beijing). After Emperor Gong of Song was captured, the Southern Song military and civilians continued their resistance against the Yuan forces by fighting along the coasts of Fujian and Guangdong. In 1279, the Yuan army decisively defeated the Song forces at the Battle of Yamen, leading to the fall of the Southern Song Dynasty.
By this point, the Southern Song, Jin, and Western Xia dynasties had all been fully incorporated into the territory of the Yuan Dynasty. However, Kublai Khan was not content with this state of affairs; his ambition drove him to pursue even greater goals. Beyond China's borders, Kublai Khan also extended his expansionist reach to neighboring countries.
Earlier, he had already used marriage alliances to force the Goryeo Kingdom to submit to the Yuan Dynasty. Later, his attention turned to Japan. The rulers of the Japanese shogunate twice refused to acknowledge Yuan supremacy. In 1281, Kublai Khan dispatched an army of nearly 200,000 troops to attack Japan. However, due to overextended supply lines and lack of naval combat experience, the Yuan forces ultimately suffered a disastrous defeat. In his campaigns to conquer Southeast Asian kingdoms, Kublai Khan also encountered numerous setbacks and achieved little success.