One of the most remarkable figures in China's history, Qin Shihuangdi, the First Emperor of Qin, had become king of the state of Qin in 246 BCE at the age of thirteen. He was a brilliant general, under whom Qin armies defeated all the other states. In 221 BCE, he united them in a realm that established China much as we know it today, and declared himself First Emperor. Across the new Chinese empire, the noble houses of the former states were abolished. The government sent its own officials to govern each area, using a great quantity of rules and regulations. Weights and measures were standardized, and even the width of axles was regulated, so that vehicles would run smoothly on the new roads that were built empire-wide. Criticism was not tolerated, and all books were destroyed except manuals on topics like agriculture and medicine. According to tradition, 460 scholars were buried alive as a warning against defiance. Hundreds of thousands of people were conscripted to build the Great Wall, as well as a huge palace and a gigantic tomb. The tomb was discovered by farmers in 1974, with its thousands of life-size terracotta figures lined up to protect the emperor. Ordinary people suffered from onerous labor service, and from harsh treatment under Qin laws.