The characteristics of each era in ancient China were as follows: The Xia Dynasty (about 21st century B.C. -about 16th century B.C.) was the first era in ancient China. Its characteristics included: - The Xia Dynasty was a society based on tribal alliances. The power of the country was scattered and there was no unified monarch. - The ruler of the Xia Dynasty was Yu. He maintained the unity and stability of the country by controlling the flood. - The social and economic structure of the Xia Dynasty was mainly agriculture and craftsmanship, and the early currency and characters appeared. The Shang Dynasty (about 16th century B.C. -about 11th century B.C.) was the second era of ancient China. Its characteristics included: - The Shang Dynasty was a powerful country with Shang Tang as its core. The country had a vast territory and the rulers implemented a central system. - The social and economic structure of the Shang Dynasty was mainly composed of agriculture and craftsmanship, and commerce and transportation had also developed to a certain extent. - The earliest currency appeared in the Shang Dynasty and created ancient characters such as oracle bone inscriptions. The Zhou Dynasty (about 11th century B.C. -256 A.D.) was an era in ancient China. Its characteristics included: - The Zhou Dynasty was a feudal dynasty led by the surname Ji. The country's territory continued to expand. - The Zhou Dynasty implemented the enfeoffment system, which granted the power of the country to the vassals to maintain the stability and unity of the country. - The Zhou Dynasty produced great philosophers and philosophers such as Confucius and Lao Tzu. - The Zhou Dynasty also created Confucianism, Taoism, Mohism, Legalism, and many other important schools of thought. The Qin Dynasty (221 - 206 AD) was a short dynasty in ancient China. Its characteristics included: - The Qin Dynasty was a powerful country with Qin Shihuang as its core. The country's territory was vast and unified China. - The Qin Dynasty achieved the unification of words and the unification of weights and measures. - Great archaeological discoveries such as terracotta warriors and horses appeared in the Qin Dynasty. The Han Dynasty (206 - 220 AD) was a glorious period in ancient China. Its characteristics included: - The Han Dynasty was one of the most glorious periods in China's history. The country's territory continued to expand, and its economy and culture developed greatly. - In the Han Dynasty, great philosophers such as Confucius, Xunzi, and Mozi appeared. - The Han Dynasty also created the imperial examination system, which promoted the development of education and culture in China. - In the Han Dynasty, great rulers such as Emperor Liu Bang and Emperor Wu of the Han Dynasty Liu Che appeared.