After the death of the Prophet Muhammad (ص), Muslims politically diverged into two main groups: one group considered the Prophet's succession to lead and manage the affairs of the Muslim community a secular matter, with Muslims choosing their own leaders; the other group considered it a divine matter, believing that God Almighty appointed the imams after the Prophet and designated them during his lifetime. Over time, various sects and schools of thought emerged, blending politics and doctrine. This book examines political and sectarian movements in Islamic history, focusing on the Assassins, who originated in Iran, and Ibn Tumart, who arose in Morocco. Readers will notice significant similarities between these two movements, despite their doctrinal differences, due to the similar circumstances preceding their emergence, the resemblance between their founders, and their organizational structures. The researcher has divided his work, a distinguished academic thesis, into three chapters: the first explores Islamic political schools of thought and the circumstances surrounding the emergence of each. The second chapter addresses the Assassins movement in Iran and contemporary states, focusing on its founder, Hassan ibn al-Sabbah. The third chapter examines the movement of Ibn Tumart in Morocco, exploring the Almohad dynasty and the figure of Ibn Tumart himself. The research concludes with significant findings beneficial to both the general reader and specialists in Islamic history. It is a unique and scholarly work, distinguished by its author's impartiality, depth of analysis, clear presentation, and elegant style.