提 要：元首制是古罗马由共和制向君主制转变的中间环节。通过前后对比可以发现，元首制下，随着内、外环境的变化，元首人选呈现出阶段性特征。元首制前期，元老阶层凭借征服者的身份、森严的社会等级制度以及自身的实力垄断了元首一职，而非元老阶层很难通过合法渠道晋升为元首；元首制后期，非元老阶层的将军们以蛮族入侵为契机，凭借军功，依靠军队的支持打破旧有的社会等级制度，成功晋级为元首。

关键词：元首制；元首；元老阶层；非元老阶层

Title: A Study of the Periodic Characteristic of Roman Principate: Taking the Change of Princep Contenders as an Example

Author:Yin Ning, Ph. D. Candidate, School of History, Beijing Normal University, Beijing, 100875, China, and Lecturer, School of History and Culture, Jishou University, Jishou, 416000, China.

Abstract:Principate was a system played an important role in the transformation from republic to monarchy in the ancient history of Rome. By comparison, it would not be difficult to find that the status of princep contenders changed along with the transformation of political situation. In the earlier stage, the senatorial class monopolized princeps’ position while none-senatorial class could hardly become Roman princeps. In the later stage of principate, the none-senatorial class took advantage of barbarian invasion and relied on their own military contribution and the support from the legionaries. They broke the limit of old social hierarchy, promoted to princeps.

Key words:Principate; Princeps; Senatorial Class; None-Senatorial Class