In view of the emphasis placed upon sectarian or group structure in this study, the most logical starting point is an examination of the earliest Shī‵ite or proto-Shī‵ite group, known as the Saba'iyya, whose name comes from its founder, one ‵Abd Allāh ibn Saba', a contemporary of ‵Uthmān and ‵Alī. There has been much disagreement and uncertainty surrounding the life of this individual and the nature of the movement named for him. Although there has been some doubt as to whether Ibn Saba' ever existed, information found in reliable sources seems to indicate his presence among the partisans of ‵Alī. Still one of the best presentations of the source materials for the activities and beliefs of Ibn Saba' and his followers, as well as a detailed and skillful analysis of these materials, is the study of Israel Friedlaender, entitled “‵Abd Allāh ibn Saba', der Begrunder der Shī‵a, und sein Judischer Ursprung.” Although some of Friedlaender's views require modification, perhaps, his general conclusions concerning the activities and beliefs of Ibn Saba' and the Saba'iyya seem to be substantially correct. The significant result of Friedlaender's work is that it demonstrates in a rather conclusive manner that Ibn Saba' and the Saba'iyya did, in fact, exist, at least from the time of ‵Alī, and that they came to entertain religious beliefs, at least some of which were adhered to by the groups that are the subject of this study.