Who could take the civil-service examinations during Taizong’s reign?

During the reign of Emperor Taizong of the Tang dynasty, the civil service examination system was in principle open to all, though in practice it was not the primary method for entering the bureaucracy.12

Candidates for these examinations generally came from two main sources:
* Local schools: These institutions provided candidates who could compete for entry into the bureaucracy.12
* Capital schools: These schools were largely restricted to the sons of the nobility and high-ranking officials.12

Despite the theoretical openness of the system, the examinations provided relatively few new entrants to the government during this period. Most officials continued to secure their positions through other means, such as hereditary privilege, promotion from the guards, or advancement from the clerical service. The examinations were primarily utilized as an alternative entry path by younger sons of the aristocracy and members of lesser families who possessed a scholar-official background.12