The Fragmentation of Mongol Power After the Yuan Dynasty

When Mongol nobles were expelled from China in 1368, their empire fractured into three major factions: the Tatars, Oirats, and Uriankhai. The Uriankhai maintained tributary relations with the Ming Dynasty through horse markets at Kaiyuan and Guangning, while the Tatars and Oirats waged endless wars across the northern steppes. This constant warfare forced the Ming to construct the Nine Frontier Fortifications.

The mid-Ming period saw the rise of Dayan Khan (1474-1543), who temporarily reunited the Mongol tribes. He reorganized Mongolia into six tumens (administrative divisions): three left-wing tumens (Chahar, Uriankhai, Khalkha) and three right-wing tumens (Ordos, Tümed, Yöngsiyebü). The Great Khan ruled from the Chahar tumen, while his deputy governed the right wing from Ordos.

The Collapse of Mongol Unity

By the late Ming period, Altan Khan of the Tümed tumen rose to prominence, expanding westward into Qinghai and Tibet while forcing the Chahar to migrate eastward. When Nurhaci established the Later Jin, tensions with Mongol tribes escalated dramatically.

In 1619, a Mongol alliance of Khalkha, Jarud, and Khorchin tribes ambushed Later Jin forces near Tieling but suffered catastrophic defeat, with several nobles captured. Chahar’s Ligdan Khan then warned Nurhaci against westward expansion, boasting of commanding “400,000 Mongol warriors.”

The Turning Point: Later Jin’s Strategic Victories

After Nurhaci’s death in 1626, his successor Hong Taiji (Emperor Taizong) exploited Mongol divisions brilliantly. Key developments included:

– 1627: The Khorchin tribe, attacked by Ligdan Khan, defected to the Later Jin
– 1628: Aohan and Naiman tribes (20,000 people) surrendered to Hong Taiji
– 1629: Kharchin leader Subudi allied with Hong Taiji against Ligdan Khan

These defections critically weakened the Chahar confederation while giving the Later Jin access to strategic passes near the Great Wall.

The Final Campaign Against Ligdan Khan

In 1632, Hong Taiji launched a massive campaign against Ligdan Khan with 100,000 troops from allied Mongol tribes. The campaign proved decisive:

1. Ligdan Khan fled westward across the Yellow River, losing 70-80% of his followers
2. The Later Jin captured Hohhot (Guihua City) and obtained the Yuan dynasty’s imperial seal
3. Most remaining Chahar nobles surrendered by 1634

When Ligdan Khan died of smallpox in Qinghai (1634), his son Ejei eventually surrendered to Dorgon in 1635, bringing the imperial seal that symbolized Mandate of Heaven transfer to the Later Jin.

The Legacy of Mongol Unification

Hong Taiji’s 1636 proclamation as Boghda Sechen Khan marked the formal incorporation of southern Mongolia into what became the Qing Empire. This achievement rested on three pillars:

1. Exploiting Ligdan Khan’s harsh rule that alienated Mongol tribes
2. Preventing Ming-Mongol alliances through strategic diplomacy
3. Implementing a carrot-and-stick policy combining military force with generous treatment of defectors

The conquered Mongols were reorganized into the Eight Mongol Banners, becoming crucial Qing military assets. This unification of southern Mongolia provided the strategic depth and cavalry forces that would enable the eventual Qing conquest of China proper.

The fall of the Mongol confederacy demonstrates how internal divisions, when skillfully exploited by a rising power, can transform the geopolitical landscape of an entire region. Hong Taiji’s Mongol campaigns remain a masterclass in frontier statecraft and military-diplomatic coordination.