隋炀帝

炀 is one of the most damning posthumous titles, given by the Tang for a ruler who 'abandons ritual and drives away the people'. The canal, the new eastern capital at 洛阳 and the Korean wars cost so much forced labor that revolts broke out everywhere, and the rebel 李密's proclamation against him gave the idiom 罄竹难书.

He was killed by his own guards in 618 at Jiangdu, today's 扬州, and the Tang took over. Remembered as a tyrant, he still left a canal that linked the Yellow River and the Yangtze and carried the empire's grain for centuries.