The first century of Islam, and particularly its first half, was a distinctive period and the earliest context for the emergence of Imami thought, in which the doctrinal propositions and principal theological components of Imami Shiism were present. However, the emergence and manifestation of these ideas and beliefs can be traced primarily within the context of the social and political developments and practical events of that period. At that time, these beliefs were less frequently explained and elaborated in theoretical terms, which itself is one of the factors that has led some to question the authenticity of the doctrinal components of the Imami theory of Imamate in the first century. In this article, adopting a historical-theological approach and using the method of analyzing historical and hadith-based propositions, it is demonstrated that groups of people at that time were known by designations such as the “Companions of Ali,” “Shiites,” “Ghulat Shiites,” “Rafidites,” and others, and were distinguished by particular intellectual and doctrinal characteristics. In addition to believing in the status of the Imamate of the Ahl al-Bayt, peace be upon them, as those chosen by God, they attributed special ranks to them. This group also regarded the principal characteristics of the Imam as appointment by God, special knowledge, infallibility and purity from disobedience, forgetfulness, and error, and being the most excellent of people after the Prophet, peace and blessings be upon him and his family. Furthermore, it is demonstrated that the establishment of the Shiite community on the basis of these fundamental beliefs took place during the same period, centered on the Ahl al-Bayt of the Prophet, peace and blessings be upon him and his family, through the propagation and following of their particular companions.