From the very beginning...
From the very beginning, Syria, which led one wing of the Qurayshi faction, did not recognize his caliphate. Other leaders of the Qurayshi faction were Talhah and Zubayr who were also disgruntled with the rule of Imam Ali ('a). They made Basrah their base and as a consequence of this rebellion the Imam was compelled to shift his capital to Kufah. In Madinah itself a number of , albeit very small, refused to give allegiance to the Imam. They were the neutralists' (Qa'idin).
Aside from political issues, an important problem was the clarification of religious issues concerning controversial matters especially in relation to emergent issues. It was for this reason that two political and, as a consequence, religious factions emerged. There were those who accepted Imam Ali's religious authority and considered it a religious obligation to follow him; they were those who were not acceptable to the Uthmanid party now represented by Syria and Basrah.
The second group consisted of those who were not prepared to accept the Imam's rule and opposed him with the motive of avenging Uthman's death. All that which went into forming the attitudes of the opponents, acquiring a more developed form in the course of time, came to be called the Uthmani creed. This creed stood in contrast to the Alawid faction to which the term Shiah came to be applied shortly afterwards.
During the developments of the period of the Imam's caliphate, a group became the followers and supporters of Imam M and gradually came to be called al-Shi'ah or Shi'is. As against them a group of people became partisans of Uthman and the Uthmanid faction and they came to be known as al-'Uthmaniyyah or 'Uthmanis. For this reason the Uthmaniyyah became the name for the religious approach that opposed Shiism.
In the course of time it came to represent the religion of the common people who took their religious beliefs and practices from the Umayyad rulers. The Umayyads considered themselves as the continuation of the earlier caliphs and considered Imam Ali ('a) as standing in contradistinction to them. During this period, the term shi'ah generally stood in contrast to the term 'Uthmaniyyah. However, the term shi'ah was not used in a univocal sense in all its applications.
Among the "Shiis" there were those who were named so merely because they were against 'Uthman and supported the Imam as the legitimate caliph.