Mongolia before Manchu occupation (between the 14th to 16th centuries)

I.  The Fragmentation Following the Yuan Dynasty's Fall:

The period known as the Little Khans (or "Period of Small Khans") was lasted from the fall of the Yuan dynasty in 1368 until the submission of the Khalkha Mongols in 1691. During these 323 years, 22 khans ruled, but power was spread among different Mongol nobles. The authority of the Great Khan was often weak and challenged. Various groups, like the Eastern Mongols and Oirats, fought for power. This resulted in short reigns filled with coups and assassinations. It weakened the Mongols.

II. Struggle for stabilization of empire: Batumöngke Dayan Khan

In the late 15th to early 16th centuries, Batumöngke Dayan Khan, a descendant of Genghis Khan, brought many Eastern Mongols together again. With help from his wife, Mandukhai Khatun, he restored the Borjigin leadership. He organized the Mongols into the "Six Tümen," creating a system that lasted for centuries. However, after he died around 1517, power divided among his descendants. This led to three separate groups in Mongolia: the Chahar Mongols, the Khalkha Mongols, and the Western Mongols.

• Chahar Mongols (Inner), Southern Mongolian nobles began submitting to the Manchus.
• The Khalkha Mongols, the primary groups in modern-day Mongolia, formally acknowledged Qing Emperor supremacy at the Assembly of Dolon Nor in 1691, seeking protection against the Western Mongol Dzungars.
• The Western Mongols (Oirats/Dzungars) preserved their autonomy the longest, establishing the potent Dzungar Khanate, which the Qing Dynasty ultimately conquered between 1755 and 1759.