The Brethren of Purity: A group of Arab Muslim philosophers, who lived in the tenth century AD in the city of Basra in Iraq, and agreed on the unification of Islamic doctrines and philosophical theories, and to them is attributed the book “Rasa’il Ikhwan al-Safa’.” Historians suggest that the Ikhwan al-Safa and Khallan al-Wafa are descended from Ismaili thought. The social classes of the “Brothers of Purity” differ; Some of them are the sons of the rich class, such as kings, princes, and ministers, and among them are the sons of the common people, such as workers, writers, and merchants, and the sons of writers, scholars, and jurists, and their categories, their names, residences, and number have not been specified. Historians have differed in their nature, doctrine and identity, but they have left their letters, which are considered an enormous encyclopedia that included the most important arts of culture that existed in their era, and it numbered fifty-two letters, the declared goal of which is “to unite in the pursuit of happiness of the soul through the sciences that purify the soul.” The “Brothers of Purity” were interested in Greek philosophies, the philosophy of Persia and ancient India, and they were merging them with Islamic philosophy in their explanation of creation theory. They aimed to bring religions and philosophy closer together, to erase the notion of contempt for philosophy among the religious, and to show that Islam and philosophy do not contradict each other. For this reason, they wrote in secret, and assembled in a way that resembled the secret political cells of the modern era. The "Brothers of Purity" were also interested in all the heavenly religions, astronomy, mathematics, music, minerals, plants and animals. In their dispute over the classification of the Brethren of Purity, some Muslim scholars accused them of heresy and atheism, and described their thought as heresy and corruption, while others considered them to be followers of the Mu'tazila, and others said that they follow the esoteric school. It was said that they were following the method of piety in concealing their identity, and it was also said that Ibn al-Muqaffa was one of them.