Excerpts from Books and Wikipedia
In the Warring States Period, the western kingdom of Qin conquered its six rivals and created a unified Chinese state. During a siege in -260, the Zhao army surrendered and the Qin commander had the entire Zhao army of 400,000 men buried alive to prevent mass revolt. Zhao never recovered and was conquered by the Qin in -228. Archeologists have recovered bones thought to be from this battle. [Furtado: 1001 Days]