Just as councils and assemblies were central to European polities for centuries, the Imperial Examination System (Keju) constituted the cornerstone of state institutions in China. This Element argues that Keju contributed to political stability, and its emergence was a process, not a shock, with consequences initially unanticipated by its contemporaries. The Element documents the emergence of Keju using evidence from early Chinese empires to the end of the Tang Dynasty in the 10th century, including epitaphs and government documents. It then traces the selection criteria of Keju and trends in social mobility over the second millennium, leveraging biographical information from over 70,000 examinees and 1,500 ministers and their descendants. The Element uses a panel of 112 historical polities to quantify Keju's association with country-level political indicators against the backdrop of global convergence in political stability and divergence in institutions. This title is also available as Open Access on Cambridge Core.