Chad Chang, age 16, of Lynn, Mass., for his question:
WHEN WAS CHINA'S HAN DYNASTY?
A series of emperors of the same family ruled ancient China for over 400 years during a period of time that came to be known as the Han dynasty.
Under Han rule, arts and sciences thrived and China became as large and powerful as the Roman Empire. The Chinese still call themselves Han people in recognition of China's achievements during this period of time.
Founder of the Han dynasty was Liu Pang. The dynasty started in 202 B.C. after the fall of the Ch'lin dynasty. The rule was divided into two periods. The Former Han dynasty lasted from 202 B.C. until 8 A.D. The Later Han dynasty lasted from 25 to 220 A.D.
The two periods were also called the Western and Eastern Han dynasties. From 8 until 23 A.D., China was ruled by Wang Mang, a revolutionary who set up the Hsin dynasty. After the Hsin fell, the Han soon regained control and the old dynasty returned for a rule of another 195 years.
Han emperors had strong centralized governments. They used a civil service examination to select officials. The examination stressed knowledge of the teachings of Confucius.
During the Han dynasty, education gained an important place. A central university was built. Poets and prose writers developed a clear style that is still famous in Chinese literature.
During the Han rule, scholars wrote long histories of China and artists produced glazed pottery and large stone carvings. The greatest invention of the Han period was paper.
Han China expanded southwest to what is now Tibet. Han warriors also conquered what are now North Korea and North Vietnam and overcame nomadic tribes in the north and west.
Overland trade routes linked China with Europe for the first time during the Han dynasty. Along the most famous route, the Great Silk Road, Chinese silk and other products flowed into the Roman Empire.
The Han dynasty collapsed because of rivalries among the scholar officials, imperial relatives, advisers and generals.
After the Han dynasty came to an end, for the next 400 years the country was divided into waring states.
The capital of the Former Han dynasty was Ch'ang an, which is now Sian. The Later Han dynasty had its capital in Lo yang. Because Ch'ang an lay west of Lo yang, the two periods came to be called the Western and the Eastern Han dynasties.
Historians consider China one of the four cradles of civilization. Other early cultures developed in the Middle East and Egypt, and in the Indus Valley of southern Asia, in what is now Pakistan.
The first Chinese civilization rose about 4,000 years ago. Asia's great deserts and mountains isolated these Chinese cultures and probably prevented contacts with other early civilizations.