The Jin Dynasty had developed an alliance with the Tuoba against the Xiongnu state Han Zhao early in the fourth century.

In 315, the Tuoba chief had been granted the title of the Prince of Dai.

After the death of its founding prince, Tuoba Yilu, however, the Dai state had stagnated and largely remained a partial ally and a partial tributary state to Later Zhao and Former Yan, finally falling to Former Qin in 376.

After Former Qin's emperor Fu Jiān is defeated by Jin forces at the Battle of Fei River in his failed bid to unify China, the Former Qin state begins to break apart.

Tuoba Si was born in 392 after his father Tuoba Gui had founded Northern Wei in 386 but before he had conquered most of rival Later Yan's territory and claimed an imperial title in 399.

His mother was Tuoba Gui's favorite consort, Consort Liu, the daughter of the Xiongnu chief Liu Toujuan.

He was born at the capital Yunzhong (in modern Hohhot, Inner Mongolia.)

Heis Tuoba Gui's oldest son, and his father was said to be so pleased by this late arrival of a son that he declared a general pardon.

(It should be noted that based on Northern Wei's official history, Tuoba Gui would only be twenty-one at this point; this might be further evidence corroborating the alternative version of his life history.)

As Tuoba Si grew, he was said to be a wise and kind young man, whose actions were all in accordance with proper protocol.

In contrast, his oldest younger brother Tuoba Shao was a frivolous and violent young man, and often received punishment from Emperor Daowu.

Tuoba Si tried to correct his brother's behavior by rebukes, but this made Tuoba Shao angry at him.

In 403, Tuoba Gui, by this point Emperor Daowu, created him the Prince of Qi.

In 409, Emperor Daowu is intent on creating Tuoba Si crown prince, but based on the Tuoba tradition that when an heir is decided upon, his mother must be put to death, the emperor forces Consort Liu to commit suicide.

Either before or after he does so, he summons Tuoba Si to explain to him that this tradition is also in accordance with Emperor Wu of Han's rationale to put to death his favorite concubine, Consort Zhao (the mother of Emperor Zhao of Han), to avoid overly great maternal influence on a young emperor.

After Tuoba Si leaves his father's presence, because of the affection that he has for his mother, he mourns greatly.

Hearing this, Emperor Daowu summons him back to the palace—and, because Emperor Daowu, in his late reign, often displays great paranoid and violent tendencies, the new crown prince's attendants suggest that he not go to the palace but hide in the country.

Tuoba Si agrees and flees the capital, Pingcheng, where Emperor Daowu had moved the capital in 398.

Meanwhile, Emperor Daowu, because of the crimes of Tuoba Shaos, had imprisoned Tuoba Shao's mother Consort Helan and planned to execute him.

Consort Helan sends her son a message, asking him to save her.

In response, Tuoba Shao assassinates Emperor Daowu, then tries to take over as emperor, attempting to seize control of the troops.

Tuoba Si, upon hearing this news, returns to Pingcheng but hides himself, while trying to gather supporters gradually.

Tuoba Shao tries to seek him out in order to to kill him, but the imperial guards gradually shift to Tuoba Si's side, and the imperial guards arrest Tuoba Shao and present him to Tuoba Si.

Tuoba Si executes Tuoba Shao, Consort Helan, and Tuoba Shao's associates.

He then takes the throne as Emperor Mingyuan.

Emperor Mingyuan sends one of his advisors, Baba Song the Duke of Nanping, to attack the Rouran, in 410 and when Baba is surrounded by Rouran troops, Emperor Mingyuan personally leads an army to relieve Baba.

Emperor Mingyuan, in contrast to to his father's dictatorial style, has instituted a council of eight officials to advise him on all important decisions, with the intent to hear different opinions and then take informed actions.

The council mostly consists of ethnic Xianbei from his tribe, but also includes Han and other ethnic groups.

This will become a tradition that his descendants will follow as well.

However, while he is known as being much more lenient than his father, he also does not tolerate wrongdoing on his advisors' part.

For example, in 413, one of his key advisors, Tuoba Qu, the Marquess of Yuancheng, suffered a major defeat at the hands of Xia forces, and then, once demoted to governorship of Bing Province (modern central and southern Shanxi), failed to carry out his task competently, and Emperor Mingyuan executes him.

He often leaves the capital, Pingcheng, to examine the defenses on the northern and eastern fronts (with Rouran and Northern Yan), to make sure that his state will be properly defended against enemies.

He also often sends armies to pacify rebelling tribes.

Emperor Mingyuan sends ambassadors to Later Qin, Northern Yan, Jin, and Rouran in 414 in an attempt to establish peaceful relationships.

The Later Qin and Jin missions are apparently largely successful, but his ambassador Huniuyu Shimen has a conflict with the Northern Yan emperor Feng Ba over Feng Ba's insistence that Huniuyu kneel to him.

Feng Ba detains Huniuyu and refuses to establish relations with Northern Wei.

Late in 414, Emperor Mingyuan begins to have his official Cui Hao (the son of his key advisor Cui Hong teach him the ancient texts of I Ching and Hong Fan—both mystical texts.

He also often asks Cui Hao to make predictions based on those texts, which often come true.

Cui Hao therefore becomes increasingly trusted and consulted by Emperor Mingyuan for important decisions.

The Rouran mission initially appears to be successful, but by the new year 415 the Rouran Khan Yujiulü Datan invades, and Emperor Mingyuan is forced to respond, chasing Yujiulü Datan back to his territory.

When Emperor Mingyuan sends his advisor Daxi Jin to pursue Yujiulü Datan, the Northern Wei forces run into severe weather and suffer many casualties from frostbite.

This initiates a pattern that is to last for centuries—often, Rouran will attack, and Northern Wei will counterattack successfully, but then become unable to score decisive victories over Rouran.

The northern regions of Northern Wei suffer a major famine in 415, causing Emperor Mingyuan to consider moving the capital southward to Yecheng (in modern Handan, Hebei), but at the advice of Cui Hao and the official Zhou Dan, who believed that such a move would quickly expose the actual numerical inferiority of the Xianbei to the Han, he keeps the capital at Pingcheng, but also pursuant to Cui and Zhou's suggestion, moves a number of impoverished Xianbei to the modern Hebei region.

In winter 415, pursuant to a peace agreement they had reached earlier, Later Qin's emperor Yao Xing sends his daughter the Princess Xiping to Northern Wei to be married to Emperor Mingyuan.

He welcomes her with ceremony fitting an empress.

However, Tuoba customs dictate that only a consort who is able to craft a gold statue by her hands could be empress, and Princess Xiping is unable to, so Emperor Mingyuan only creates her an imperial consort, but within the palace honors her as wife and empress.

The Northern Wei Dynasty unifies the Northern portion of the Chinese Empire, which will have three competing dynasties—Northern Wei, Northern Yan and Northern Liang, while …

Emperor Mingyuan's wife Consort Yao had died in 420, and he posthumously honored her as an empress.

The Emperor suffers a major illness in 422, apparently caused by medicines that alchemists had given him that were supposedly capable of extending life spans.

He consults Cui Hao on what he should do to prepare for events after his death.

Cui Hao predicts that he will recover, but advises him to create his oldest son, fourteen-year-old Tuoba Tao, the Prince of Taiping, crown prince, then transfer some of the authorities to the crown prince so that his own burdens could be lessened.

Baba Song also agrees, and Emperor Mingyuan creates Tuoba Tao crown prince, and further has Crown Prince Tao take the throne to serve as the secondary emperor.

He commissions his key advisors Baba, Cui, Daxi Jin, Anchi Tong, Qiumuling Guan, and Qiudun Dui to serve as the Crown Prince's advisor.

From this point, Crown Prince Ta rules on most matters, particularly domestic matters, while Emperor Mingyuan himself only rules on important matters.

Later in 422, after hearing about the death of Liu Yu (who had seized the Jin throne in 420 and established Liu Song), Emperor Mingyuan breaks off relations with Liu Song and calls his council, informing the advisors that he plans to attack and seize three major cities south of the Yellow River from Liu Song—Luoyang, Hulao, and Huatai, despite Cui's opposition.

He commissions Daxi as the commander of the forced to attack Liu Song.

Emperor Mingyuan also starts a major building project in 423—the building of a wall on the northern borders to defend against Rouran attacks.

Emperor Mingyuan dies in winter 423, and Crown Prince Tao takes the throne as Emperor Taiwu.

Emperor Mingyuan soon after the Chinese/Xianbei Northern Wei dynasty had captured most of modern Henan from the Liu Song dynasty, and his son Tuoba Tao had succeeded to the throne as Emperor Taiwu.

Mouhanheshenggai Khan, Yujiulü Datan, has heard of Mingyuan's death.
anhe Rouran, a confederation of nomadic tribes on the northern borders of China Proper, had attacked almost immediately.

Taiwu had engaged Rouran troops, and been surrounded by them on the very first engagement, but he had fought his way out of danger.

He initiates near-annual attacks against the Rouran, and each year, Rouran forces will continue to elude him by retreating north, only to return south after he withdraws.

Taiwu had become a devout Taoist soon after taking the throne, and it is around this time that the Taoist reformer Kou Qianzhi becomes well-known: the prime minister Cui Hao, who becomes a follower of Kou, often praises him before the Emperor.

Taiwu is pleased by Kou's prophecies, which imply that he is divine in origin, and he officially endorses Kou's proselytization of his state.

Emperor Taiwu reestablishes peaceful relations with Liu Song in 425.