There are several Mongol invasions of Tibet. The earliest is the alleged plot to invade Tibet by Genghis Khan in 1206, which is considered anachronistic; there is no evidence of Mongol-Tibetan encounters prior to the military campaign in 1240.
The first confirmed campaign is the invasion of Tibet by the Mongol general Doorda Darkhan in 1240, a campaign of thirty thousand troops that results in five hundred casualties.
The campaign is smaller than the full-scale invasions used by the Mongols against large empires.
The purpose of this attack is unclear, and is still in debate among Tibetologists.
Then in the late 1240s Mongolian prince Godan invites Sakya lama Sakya Pandita, who urges other leading Tibetan figures to submit to Mongol authority.
This is generally considered to have marked the beginning of Mongol rule over Tibet, as well as the establishment of patron and priest relationship between Mongols and Tibetans.
These relations are continued by Kublai Khan, who founs the Mongol Yuan dynasty and grants authority over whole Tibet to Drogön Chögyal Phagpa, nephew of Sakya Pandita.
The Sakya-Mongol administrative system and Yuan administrative rule over the region lasts until the mid-14th century, when the Yuan dynasty begins to crumble.
In the early seventeenth century, the Oirat Mongols again conquer the region and establish the Khoshut Khanate.
From then, the Mongols intervene in Tibetan politics until the Qing conquest of Mongolia and Dzungaria.
