Muslim societies encompass widely diverse economic, political and social structures and relations. In spite of their diversity, their members share the basic core beliefs and practices which Islam sets forth in the ‘five pillars’. They enjoin the believers to bear witness to the oneness of God, to perform the five daily prayers, to fast during the month of Ramadan, to pay annual alms and, if possible, to go on the pilgrimage to Mecca at least once. These fundamental elements of belief and practice endow Islam with its essential unity, for they are agreed upon by all Muslims as norms which they, with varying degrees of success, seek to fulfil. The degree of emphasis put on each one of them is, nevertheless, highly variable throughout Muslim communities, societies and traditions. Beyond these minimal and formal requirements, diversity reigns. In addition to the core beliefs and a number of common Islamic symbols, there are numerous ideological and practical accretions present in all Muslim societies which account for the actual diversity of Islam. Muslim societies thus differ not only in their political, economic and social-structural arrangements but also in their ritual practices and religious institutions. Orientalists and anthropologists have for long struggled with the problem of how best to conceptualise and account for the observable diversity of religious belief and practice in various Muslim societies and communities.