A family member is a family that is related to the royal family through marriage. In the whole process of feudal history, the phenomenon of the dictatorship of foreign relatives in the Han Dynasty was particularly prominent. On the surface, the reason for the emergence and development of this phenomenon is that the queen mother supports the family, but the most fundamental reason is the strengthening of feudal imperial power. After the death of Liu Bang, the emperor of the Han Dynasty, Liu Ying, the emperor of the Han Dynasty, succeeded to the throne, and during his reign, the government was controlled by the then empress dowager Lu Pheasant. However, the feudal society does not recognize women, even if the queen of Lu has the talent to govern the country, it is still not accepted by the orthodox society, in order to better control the government, she tried her best to support her mother's family, and then the princes and kings raised troops and swept away the Lu family. Emperor Wen of the Han Dynasty succeeded to the throne, Dou Yifang was the queen, and after the death of Emperor Wen, Emperor Liu Qi of the Han Dynasty succeeded to the throne, and the Empress Dowager Dou began to cultivate her own group of cronies. Since then, the problem of the dictatorship of foreign relatives in the Han Dynasty has become more and more serious. In the political environment at that time, the power of the entire dynasty was firmly in the hands of the emperor, and there was no force to restrict the development of imperial power. 
1. The political reasons for the dictatorship of foreign relatives in the Han Dynasty (1) The strengthening of the monarch in the early years of the Han Dynasty The monarch system has not yet developed and perfected, whether it is a king with a different surname, a king with the same surname, or a group of meritorious heroes, it is a serious threat to the monarch system. Therefore, the emperor needs to use some political groups, suppress their rights, and maintain the feudal monarch**. The prime minister system has existed for a long time, and in the early years of the Han Dynasty, the system of the Qin Dynasty was fully inherited, and the power of the prime minister was very large, and all major decisions in the court were implemented by the prime minister to assist the emperor, and gradually there was a contradiction between the imperial power and the prime minister's power. During the period of Emperor Wu of the Han Dynasty, in order to strengthen the monarch and weaken the rights of the prime minister, the "Zhong Dynasty" was established, and the "Zhong Dynasty" was responsible for assisting the emperor in handling government affairs, with decision-making power and executive power. Emperor Wu of the Han Dynasty was afraid of the "Chinese Dynasty" to control the government, so he often replaced these **, which strengthened the mobility of the ** and avoided the growth of the minister's power to threaten the imperial power. However, this system has created problems in the process of development. Many emperors in the Han Dynasty believed that blood relatives were far more reliable than others, for example, Liang Shang, the general during the period of Emperor Shun of the Han Dynasty, was ** because of illegal acts, but Emperor Shun of the Han Dynasty said, "The general's father and son are close to me, but you Cao is jealous" This shows how much the emperor trusted the foreign relatives group at that time. Unlike the group of foreign relatives, the clan forces with the same surname at that time were often feared by the emperor. During the reign of Liu Bang, the ancestor of the Han Dynasty, Zeng Guangfeng was the king of the clan with the same surname, and he hoped that these kings with the same surname could assist ** and support the Han family. However, it backfired, and those kings with the same surname continued to expand their power in their fiefdoms, and began to plot for imperial power when their power grew. For example, during the "Rebellion of the Seven Kingdoms" during the reign of Emperor Jing of the Han Dynasty, the princes and kings at that time were dissatisfied with the "cutting of the feudal domain" and jointly rebelled in the name of "Qing Jun's side". In the eyes of these monarchs, the relatives were different from the children of the clan who could compete with them for the throne, and the relatives and the emperor belonged to a community of interests, so the group of relatives in the Han Dynasty was often given important responsibilities. In general, the power given by the emperor to the group of relatives was mainly due to the need to strengthen the imperial power, especially after the rebellion of the vassal states with the same surname, the emperor relied more on the group of relatives. 
2) The Empress Dowager took power, and the imperial succession system during the Han Dynasty was not perfect enough, and many of the emperors who succeeded to the throne were extremely young, for example, Emperor Han He was only ten years old when he succeeded to the throne, Emperor Han was only three months old when he succeeded to the throne, and Emperor Han Chong was only two years old when he succeeded to the throne. In order to avoid chaos in the regime, maintain the stability of the rule, and prevent the Zong clan from usurping the throne, the empress dowager is often in charge to stabilize the political situation. But the queen mother called the court, often there are limitations, as a deep palace women, their understanding of the entire court is very limited, in order to maintain the stability of the political situation, they have to rely on their father and brother, in this case, the power of relatives will naturally be reused, and gradually these relatives will be powerful in the court. For example, during the period when the Empress Dowager Dou grasped the government, the fathers, sons and brothers of the Dou family were all in high positions, and the power of the Dou family was tilted towards Beijing. (3) Personal reasons of the rulerIn feudal dynasties, when the ruler chooses a successor, most of them choose to inherit the throne by their own heirs. This feudal inheritance system laid the groundwork for the occurrence of the phenomenon of the dictatorship of foreign relatives. There were many emperors who would rely on the eunuch group to divide the power of the group of foreign relatives, so as to achieve the goal of regaining power. However, after the emperor became in power, he would appoint a new group of relatives to help him manage the government. Under this cycle, the phenomenon of the dictatorship of foreign relatives is difficult to be a**. And in the process of taking power in the foreign relatives group, they will take the initiative to choose the emperor who is easy to control, after the death of Emperor Hui of the Han Dynasty, the young Liu Gong was established as the new emperor, and soon Liu Gong was deposed, and the young Changshan King Liu Yi was established as the new emperor, in this process, the relatives of the Lu family have always held the power of the court. In addition to the issue of age, the personal ability of the ruler was also largely due to the fact that many Han rulers ignored the government and handed over power to their relatives. Under the auspices of the group of relatives, the government can also run smoothly, but after a long time, the ruler will often rely on these relatives, for example, when Emperor Cheng of the Han Dynasty resigned twice, but Emperor Cheng of the Han Dynasty not only did not allow it, but also begged his uncle to "concentrate on stubbornness, and assist me not to catch it". Wang Mang also offered to resign during the time of Emperor Han Ai, but Emperor Han Ai also deeply retained, which eventually led to Wang Mang's usurpation of Han. In addition, there are many emperors who did not leave heirs, in this case to elect the same surname of the vassal king to inherit the throne, this process is very difficult, those who have been helped by the power of foreign relatives, can successfully ascend to the throne, so after they successfully ascended the throne, on the one hand, in order to thank the foreign relatives group, on the other hand, because their power has not yet grown, the power will often be controlled by foreign relatives. 2. The economic reasons for the dictatorship of foreign relatives in the Han Dynasty (1) The rich food and wealth of foreign relatives and the growth of the economic power of foreign relatives are also important reasons why they can control the government of the court. In the early years of the Han Dynasty, Quanfu inherited the system of the Qin Dynasty, so in terms of promotion, the "military merit system" was adopted. During the Gaozu period of the Han Dynasty, only the three relatives of Lu Gong, Lu Ze, and Lu Shizhi could be named Hou by virtue of their own merits. However, in the period of the Empress Lü, this system was destroyed, and when the Empress Lü was knighted, it was often divided according to the relationship with him. During the Han Dynasty, the princes' food estates were very rich, and in this case, the power of the Lu family grew and their economic strength also expanded rapidly. During the period of Emperor Wu of the Han Dynasty, in order to grasp the phenomenon of changing the autocracy of the old relatives, he continued to support new relatives forces, among which Wei Qing, Huo Quzhi and others became the new relatives and magnates, of course, at that time did not cause the phenomenon of the dictatorship of relatives, but this laid an economic foundation for the rise of Huo Guang later. (2) The development of land annexationIn addition to the fiefs enjoyed after the abundance, these foreign relatives also encroached on land through various means. The first is the encroachment on "public land", which refers to mountains, forests, rivers and confiscated land. At that time, foreign relatives often used their power to take possession of these "public lands" and then lease them out at high rents. Secondly, these foreign relatives often use their power to buy some "public land" or "private land", because of their special status, they need to pay far less than the market when buying land. Finally, these relatives often use their power to seize other people's land. 
Summary: The issue of the dictatorship of foreign relatives ran through almost the entire development of the Han Dynasty, which was the choice of the ruler to strengthen his power in the process of governance, but with the development of time, this system gradually became distorted, and even threatened the rule of the Liu family, changing the development process of the Han Dynasty. However, the emergence and development of foreign relatives is based on the rule of imperial power, so this system is a vassal of the monarch, once it leaves the support of the ruler, this system naturally loses the basis for its existence and development.