In 595, king Sambhuvarman (r. 572–629) of Lâm Ấp, a Cham kingdom with its capital Kandapurpura located around modern-day Huế, prudently sent tribute to the Sui.

[2] In 601, the Chinese official Xi Linghu forwarded an imperial summons for Phật Tử to appear at Chang'an, the Sui capital.

[3] In 602, Emperor Wen of Sui ordered general Liu Fang to launch a surprise attack on Phật Tử from Yunnan with 27 battalions.

Liu Fang then ordered troops to dig booby traps and covered them with camouflaged leaves and grass.

[8] On the route back to China, the invading force was hit by an outbreak of disease which killed large numbers of the officers and men, including Liu Fang.