The Oirat Ascendancy and Internal Strife

The mid-15th century marked the zenith of Oirat Mongol power under Esen Taishi, whose forces achieved a stunning victory over the Ming Dynasty at the Battle of Tumu Fortress in 1449. This triumph, which saw the capture of Emperor Yingzong, emboldened Esen to challenge Toghtoa Bukha, the nominal Great Khan of the Mongols. Their rivalry stemmed from deep-seated tensions: Toghtoa Bukha had initially opposed invading Ming territory, only participating halfheartedly in the campaign.

Historical records from the Veritable Records of Ming Yingzong reveal how Esen orchestrated Toghtoa Bukha’s downfall in October 1451, seizing his family, subjects, and territory. The deposed khan fled across the steppe before being assassinated, clearing the path for Esen’s unprecedented move—in 1453, he declared himself “Great Yuan Tian Sheng Khan,” becoming the first non-Chinggisid ruler to claim the Mongol imperial title since the Yuan Dynasty’s collapse.

The Cycle of Violence and Decline

Esen’s reign proved short-lived due to his brutal policies. His poisoning of Alag Khan’s son triggered a rebellion; in August 1454, Alag’s forces ambushed and killed Esen near the Kükün Khan Mountains. This assassination plunged the Mongols into renewed fragmentation, with the Oirats gradually retreating westward under pressure from eastern Mongol tribes.

Meanwhile, Ming officials debated exploiting the chaos. General Shi Heng advocated seizing the legendary Imperial Seal, but scholar Li Xian countered that such symbols represented “ill-fated dynasties.” Emperor Yingzong, traumatized by Tumu, rejected military adventures amid economic strain from natural disasters.

The Chinggisid Restoration and Dayan Khan’s Legacy

The eastern Mongols (Tatars) revived Chinggisid legitimacy under Manduul Khan (r. 1471) and his successor Dayan Khan (1479-1543). Dayan’s unification of the Six Tümen (tribal federations) ended a century of noble infighting, though his realm remained smaller than Esen’s empire. His mixed relationship with the Ming—alternating between raids and tributary missions—reflected pragmatic economics rather than Yuan restoration ambitions.

Dayan’s administrative reforms replaced Yuan remnants with traditional Mongol structures, yet his decentralized system sowed seeds for future division. By his death, the Tatars had strengthened economically and militarily, incorporating captured Ming craftsmen to enhance metalworking—a critical advantage given their chronic iron shortages.

The Century of Conflict (1540s-1570s)

The 16th century witnessed escalating violence along the Ming northern frontier. In 1550, Altan Khan’s forces breached defenses near Beijing in the “Gengxu Incident,” exposing Ming military decay. Garrison troops, plagued by corruption and understaffing, failed to repel Mongol cavalry, allowing widespread plundering before Altan’s withdrawal.

Ming defensive tactics evolved with wagon forts and firearms, as seen in Qi Jiguang and Yu Dayou’s reforms. However, smuggling and collusion between border troops and Mongols undermined security. The Ming’s economic blockade proved counterproductive, fueling resentment and raids.

The Altan Khan Accord and Its Aftermath

The 1571 peace agreement with Altan Khan marked a turning point. Triggered by the defection of Altan’s grandson Baga Achi, the accord established tribute trade, granting Altan the title “Obedient and Righteous King.” This pragmatic solution reduced Ming military expenditures by 70% and brought stability to the western frontier, though eastern Mongols continued hostilities in Liaodong.

Historical Assessment

The Ming-Mongol conflict spanned three phases:
1. Ming Offensives (1367-1424): Zhu Yuanzhang and Yongle’s aggressive campaigns pushed Mongols into remote regions.
2. Strategic Defense (1424-late 1400s): Ming retrenchment after Tumu, while Mongols reoccupied border zones.
3. Stalemate (1500s-early 1600s): Dayan Khan’s successors raided extensively until the Manchu threat emerged.

While Mongols scored victories like Tumu, Ming forces won most major engagements (6 of 9 decisive battles). The conflict’s legacy was mutual exhaustion—by 1600, both sides faced the rising Manchu threat that would eventually dominate them. As the Ming Shi concluded, border strife “persisted until the dynasty’s end,” a testament to the intractable nature of steppe-sedentary relations.