The article deals with some aspects of the theory of state and gover- nance in Islam. As a source of research is taken the famous medieval treatise al-’Ahkam al-sultaniyya wa-l-vilayat ad-diniyya (“Laws of Power and Religious Rule”) whose authorship is attributed to the known Islamic theologian Abu-l-Hasan al-Mawardi. This treatise was created in the XI century in a period when the Arab Caliphate was going through hard times of degradation of the state and its traditional institutions. The main attention in the article is given to the actual and complex problem of the correlation of the powers of the Caliph and Emirs - the rulers of the regions. The ar- ticle gives an estimate of the meaning of the treatise al-’Ahkam al-sultaniyya.