 After the Battle of Xiangyang, China could not enjoy the protection of natural barriers any more and so it collapsed in just a few years, with the final battle being the relatively short naval Battle of Yamen in 1279.The battle consisted of skirmishes, ground assault, and the siege of the twin fortified cities of Fancheng and Xiangyang in modern-day Hubei, China.Lü Wenhuan, commander-in-chief of the Southern Song dynasty, surrendered to Kublai Khan in 1273.