The Han empire (206 B.C.–A.D. 220) at its height rivaled that of Rome in the extent of its territories, the number of inhabitants, and its power over neighboring states. In the late second and third century, however, as imperial power waned, control of the country moved into the hands of powerful landowners who had absolute dominion over their estates. Watchtowers, such as that represented by this spectacular architectural model, were erected to help protect the inhabitants of such estates from both neighboring threats and those posed by nomads who were moving into China and themselves gaining control of various regions. The building seen here rises to an impressive height within a walled courtyard secured by a heavy gate. Shields, crossbows, alarms, gongs, and watchmen appear on its multiple floors. The tower's grand scale, complex structure, and formidable defense system illustrate the staggering power and wealth of the gentry class in the third century.