The society has entered a mature stage. The Tang Dynasty after the Sui Dynasty was the heyday in the development history of China's feudal society. Just as the Han Dynasty was the successor to Qin's policies, the Tang Dynasty's historical mission was to continue the Sui Dynasty's unfinished business. Mr. Chen Yinke pointed out very accurately: "The Li and Tang Dynasties lasted for three hundred years, but the Yang and Sui Dynasties lasted only a short time. The rules and regulations of the two dynasties were almost the same, so they can be regarded as one." Like the Sui Dynasty, the central government of the Tang Dynasty implemented the system of three provinces and six ministries. The three provinces of the Tang Dynasty were Zhongshu Province, Menxia Province and Shangshu Province. The chief and deputy chiefs of Zhongshu Province are Zhongshu Linghe and Shilang, who are subordinate to Zhongshu Sheren and are responsible for drafting imperial edicts. The chief and deputy officials of the Menxia Province are Shizhong and Shilang, who are subordinate to Shizhong. They are responsible for reviewing the edicts drafted by the Zhongshu Province and approving the memorials of the Shangshu Province. The chief and deputy chiefs of the Shangshu Province are Shangshu Ling and Zuo Pushe, and there are left and right ministers under them. The province has jurisdiction over the six ministries of civil service, household affairs, rituals, military affairs, punishment, and industry, and is responsible for the implementation of decrees formulated by the central government. Because Emperor Taizong of the Tang Dynasty once served as Shangshu Ling, but later his ministers avoided this position and it was in vain, so Zuo Pushe actually became the highest official of Shangshu Province. In the early Tang Dynasty, the highest officials of the three provinces were prime ministers. At that time, there was also a political hall in Menxia Province, which was a place where the prime ministers of the three provinces discussed military and state affairs. The emergence of the Two Taxes Law marked the final maturity of the feudal economy. This means that the feudal palace's personal control over peasants has been relaxed, and super-economic exploitation has been alleviated. The Two Taxes Law is a tax law created by Yang Yan, the Prime Minister of Tang Dezong era. The rent adjustment method, which mainly collected grain, cloth and other physical goods, was changed to mainly collecting money, with taxes collected twice a year, which was called the two tax law. Because the annual average land system declined at the end of Wuzhou, the rent adjustment law in the early Tang Dynasty was no longer applicable, and the two tax law was implemented in the first year of Jianzhong by Emperor Dezong of the Tang Dynasty. The Two Taxes Law was a major change in my country's ancient tax system. It came into being after the collapse of the land equalization system and the rent-and-yong adjustment system, the rise of farmland, unrealized acres of land, population exile, distortion of household registration, and the Tang government's fiscal revenue difficulties. This tax law was very progressive at the time and produced good results. Not only did the number of government-controlled household registrations increase significantly, tax revenue also increased significantly, which greatly improved the economic situation of the Tang Dynasty. The Tang Dynasty had relatively stable politics, prosperous economy, and extensive foreign exchanges. It was the highest peak of my country's feudal society. The Song Dynasty is the era in Chinese history that inherited the Five Dynasties and Ten Kingdoms and started with the Yuan Dynasty. It is divided into the Northern Song Dynasty and the Southern Song Dynasty. 960 Later Zhou Dynasty general Zhao Kuangyin wore a yellow robe and established the Song Dynasty. The Zhenzong and Renzong periods entered a prosperous period. In the early Northern Song Dynasty, centralization of power was strengthened and the problem of separatist vassal towns was solved. A social crisis emerged in the mid-term, which was alleviated by Wang Anshi's reforms. The new laws promoted by Wang Anshi include equalization of transportation, green crops, exemption from labor, market changes, Baojia, Baoma, equalization of taxes on square fields, etc. The political system of the Song Dynasty generally followed that of the Tang Dynasty. However, the prime minister was no longer held by the governors of the three provinces, but Tong Zhongshu Menxia Ping Zhangshi was appointed as the prime minister. A deputy prime minister was also added to participate in political affairs, which is commonly known as the ruling party. Together with the prime minister, it is called the "chief executive". The power of the prime minister in the Song Dynasty shrunk significantly, and he was only responsible for administrative functions. The Zhongshu family and the Privy Council are collectively known as the second government, and they have great civil and military power. There are also three departments: Salt and Iron Department, Household Department and Duzhi Department, which are in charge of financial power. In this way, the three ministers, the prime minister, and the privy council made the three powers check and balance each other, thus weakening the power of the prime minister and strengthening the imperial power. The Song Dynasty also established admonishment courts and admonishment officers in addition to the Yushitai. These are supervisory agencies responsible for matters such as impeachment. In order to strengthen the centralization of power and prevent the generals from seizing power, Song Taizu eliminated the important position of the Imperial Guards, and also relieved the military attachés. The leading organizations of the Imperial Army were changed to the Palace Front Department and the Guards Department, respectively. The infantry army commanders and the cavalry army commanders commanded the troops. A Privy Council was established at the center to take charge of military affairs. The Privy Council was directly responsible to the emperor and no other officials were allowed to interfere. The Song Dynasty's military deployment can be described as "strong trunks and weak branches" and "defending the inside and leaving the outside weak". The army of the Song Dynasty was divided into four types, namely, the forbidden army, the Xiang army, the rural army, and the vassal army. The Forbidden Army was the central army and the main force of the Song Dynasty army. The Xiang army is the town army of each state and is controlled by the local governor. The rural soldiers are strong men selected according to the organization. Fan soldiers are non-Han troops guarding the border. The emergence of "Jiaozi" is the result of the prosperity of commodity exchange and the expansion of the market. Correspondingly, ancient Chinese civilization reached its highly developed stage in the Tang Dynasty. However, the maturity of feudal culture and the formation of the climax of feudal culture did not occur in the Tang Dynasty, but in the Song Dynasty, because the highest level of civilization is not poetry, but philosophy. When talking about the characteristics of the occurrence of philosophy, Hegen once said: "When the Ionian city-state in Asia Minor declined, Ionian philosophy rose accordingly.", "In Athens, due to the changes in the lives of ordinary people, corruption, the period of prosperity of philosophy will come instead." This characteristic seems to be completely in line with China's national conditions. When the prosperous economy of the Tang Dynasty began to decline with the separatism of feudal lords and towns, the "Cheng-Zhu Neo-Confucianism" that reflected the essence of life began to rise in the poor and weak Song Dynasty, and has ruled China for nearly seven centuries. During the Song and Song Dynasties, national integration and commodity economy developed unprecedentedly, foreign exchanges were frequent, and culture and art developed rapidly. It was a golden period in Chinese history. The Yuan Dynasty was the first unified dynasty established by ethnic minorities in Chinese history. Kublai Khan promoted "Han Law", attached great importance to agricultural economy, and protected agricultural production. Politically, the centralization of power was strengthened, the power of the Mongolian aristocracy was weakened, and the aristocratic fiefdoms were converted into land grants.

Although the implementation of "Han Law" was accompanied by sharp struggles between the reformists and conservative forces within the Mongolian aristocracy, which even led to bloody conflicts, it weakened the backward factors of the Mongolian people themselves and accelerated their move towards feudalization. The rule of the Yuan Dynasty They also gained broader support and cooperation from the Han landlord class, which was conducive to the consolidation of the Yuan Dynasty's rule and social progress. The great unification of the Yuan Dynasty finally formed the second great national integration and cultural convergence in the history of our country. This kind of integration and convergence is much larger than the first time. Its ethnic integration includes the Arabs of Central Asia, and its cultural convergence includes Arab culture and European culture. Moreover, this integration and convergence is more stable and deeper. In summary, from many aspects such as politics, economy, culture, military and so on, it can be concluded that the Sui, Tang, Song and Yuan dynasties were the mature stage of my country's feudal society.