The Chams had initially been closely tied to Chinese cultural and religious traditions but wars with neighboring Funan, an Indianized kingdom located around the Mekong delta, and the acquisition of Funanese territory in the fourth century had seen the infusion of Indian culture into Cham society.

Cham King Yang Mah II in 431 commands over one hundred boats in a looting expedition along Jih-nan’s coast in Tonkin, held by China’s Liu-Song dynasty.

In his absence, the Liu-Song retaliate by laying siege to Ch’u-su, breaking it only after severe weather compels them to withdraw.

Yang Mah’s troops, while fighting on Tonkin, attempt, unsuccessfully, to enlist the aid of Funan soldiers.

Skirmishing continues sporadically between the Chinese and the Chams.