Eunuchs were seen as the third gender beyond the male and female in a certain extent, and this gender contributed to the positions of the eunuchs, who became the important figures of the political life in the Early Byzantine Empire. In the reign of the Theodosian House, the eunuchs achieved the social and political influence surpassing that of previous eras, because of the internal need of the political system of the Early Byzantine Empire and the special political setting at that time. As the outsiders who suffered from bodily incompleteness, the capable eunuchs could be trusted by the emperors in the Early Byzantine Empire, and they could play the roles in the political life to protect the imperial power and check other political forces. In fact, the eunuchs were the agents of the emperors, and they usually attached themselves to the imperial power. In concomitance with the sovereign institution, the participation in the political affairs of eunuchs was the long-term existence in the political structure of the Early Byzantine Empire. Finally, accompanied by the expansion of the imperial power in the Early Byzantine Empire, the participation in the political affairs of eunuchs had the feature of institutionalization.