The administration of kazas, or cantons, was usually entrusted to the cadis and the holders of the more important fiefs; the sanjaks, or departments, were ruled by alai beys or mir-i-livas (colonels or brigadiers), pashas with one horsetail; the vilayets, or provinces, by beylerbeys or mir-i-mirans (lord of lords), pashas with two horse-tails; these were all originally military officers, who, in addition to their administrative functions, were charged with the duty of mustering and commanding the feudal levies in war time.
Above them were the beylerbeys of Anatolia and Rumelia, who served under the orders of the commander-in-chief.
The duties of the other viziers were limited to attending the divan; they were called kubbe or cupola viziers from the fact that the council met under a cupola; they were pashas with three horse-tails, and were attended by large retinues, having generally achieved distinction as beylerbeys.
The beylerbeys were replaced in 1587 by pashas sent triennially by the Porte.
From about 1518 till the death of Uluch Ali in 1587, Algiers was the main seat of government of the beylerbeys of northern Africa, who ruled over Tripoli, Tunisia and Algeria.