14th century in Mongolia

The War of the Two Capitals (simplified Chinese: 两都之战; traditional Chinese: 兩都之戰), or the Tianli Incident (simplified Chinese: 天历之变; traditional Chinese: 天歷之變), was a war of succession that occurred in 1328 in the Yuan dynasty. It was a war of succession fought between the forces based in the Yuan capital Khanbaliq (Dadu, modern Beijing) and the forces based in the summer capital Shangdu after the death of Yuan emperor Yesün Temür in Shangdu. The clash between the two groups was the bloodiest and most destructive succession in all of Yuan history. The War of the Two Capitals was less about ideology and more a struggle to advance individual family interests through political alliances and military strength. It ended with victory for the Khanbaliq group, but it took a few years for the last remnants of its opponents to give up.