Shaykhism is one of the youngest schools in the history of Imamiyyah (Twelver Shiism). The Theory of "Forth Pillar (Rukn-i-Rabi’)" is one of the most famous theories attributed to this school, the different branches of which do not have a common notion of it. Besides, they disagree over the person to whom the aforementioned theory could be attributed."Ahmad Al-Ahsa’i", "Sayyed Kazim Al-Rashti" and "Muhammad Karim Al-Kirmani" have been nominated to be the theorizer by different Shaykhi or non-Shaykhi scholars.
This Article identifies four components in the structure of Theory:
1) The literature based on Quadr-hierarchy of "God, Prophet, Imam, and perfect Shia". 2) The Hierarchy of Secret-Men (Qura-yi-Zahirah). 3) Their Unity or Multiplicity. 4) Their Duties and roles.
Although the foundation of Theory could be recognized in Al-Ahsa’i’s works, by concentrating on these four components, I shall demonstrate that Sayyed Kazim Al-Rashti should be elected as the main theorizer of Theory.