On March 19, 1279, a Mongolian victory at the naval Battle of Yamen ended the Song Dynasty in China. From the article:
"Song Dynasty falls as Mongols complete conquest of China | OUPblog
March 19th 2012
This Day in World History
March 19, 1279
The Song Dynasty ruled parts of China for more than three centuries. That reign ended on March 19, 1279, when a Mongol fleet defeated a Song fleet in the Battle of Yamen and completed its conquest of China.
The Song began ruling China in 960, but the Song state was constantly under pressure from non-Chinese peoples to the north and west. After years of fighting, the Jurchen people overran the Song in 1127. The Jurchens set up a new dynasty, the Jin, in northern China while the Song remnant fled to the south, creating the Southern Song.
Kublai Khan. Source: Wikimedia Commons.
Pressure on that state from outside China resumed in the early 1200s, when Genghis Khan led the Mongol people on their great expansion. They overran the Jin state and by the 1260s — under their new leader, Kublai Khan — began to threaten the Southern Song. The Song had a chance to avoid conquest when Kublai sent an emissary to discuss peace. The head of the Song government had the diplomat arrested, infuriating the Mongol leader and provoking an assault on Song territory beginning in 1267.
After obtaining Xiangyang (modern Xianfan) in 1273, the Mongols gained access to the Yangzi River — and the chance to penetrate deep into Song territory. More and more Song land fell into Mongol hands, and the government moved further south. It took refuge in Guangzhou and eventually fled the mainland by boat to offshore islands.
Finally, in March 1279, the Mongol navy engaged the Song fleet and defeated it. The last Song prince drowned in the battle, perhaps because he was thrown into the water by a despairing Song official. The Mongols quickly ended remaining resistance, and China — for the first time in its history — was entirely in foreign hands."