The imperial examination was a civil service examination system in Imperial China to select candidates for the state bureaucracy. Although there were imperial exams as early as the Han dynasty, the system became the major path to office only in the mid-Tang dynasty, and remained so until its abolition in 1905. Since the exams were based on knowledge of the classics and literary style, not technical expertise, successful candidates were generalists who shared a common language and culture, one shared even by those who failed. This common culture helped to unify the empire and the ideal of achievement by merit gave legitimacy to imperial rule.