Weber's theoretical legacy contains only fragments of thinking about Islam, primarily in the texts and monographs that as the main object of study did not have this religion. This fact is a big problem to contemporary researchers who want to reconstruct Weber's perception of Islam and positioning it in its theoretical and methodological coordinates. However, this barrier gives rise to modern researchers to engage in the challenge of reconstruction of the mentioned segment Weber's thoughts. This paper is an attempt of such a reconstruction. The paper analyzes the emergence of Islam, ie. spatial and social context of the founding of the Islamic religious dogma. The author starts from the hypothesis that in Weber's theoretical and analytical equation the importance of urban areas for the development and spread of Islam is absent. Also, in the paper author points to another error that Weber makes. Weber classified Islam in the category of warrior religion, and ignored the role of trade and commercial bed in the formulation of Islamic dogma and the (economic) practices. In order to more adequately respond to the request 'placement' of Islam in the theoretical coordinates of Weber's sociology (of religion), author of the paper emphasizes the universality of the rationalization process, proving that Islam is one of the better examples of substantive rationality in the religious domain (because Islamic dogma implies a holistic approach to the believer and the high level of submission to the sacred text in all areas of its life).