In the Ottoman Empire, the Grand Vizier (Turkish: Sadrazam) was the prime minister of the Ottoman sultan, with absolute power of attorney and, in principle, dismissible only by the sultan himself. He held the imperial seal and could convene all other viziers to attend to affairs of the state; the viziers in conference were called "Kubbealtı viziers" in reference to their meeting place, the Kubbealtı ('under the dome') in Topkapı Palace. His offices were located at the Sublime Porte.
The term “vizier” was originally a denomination used by the Abbasid Dynasty in the 8th century AD. This position then came to the Ottomans in the early 14th century by way of the Seljuks of Anatolia.
During the nascent phases of the Ottoman state, "vizier" was the only title used. The first of these Ottoman viziers who was titled "Grand Vizier" was Çandarlı Halil Pasha the Elder. The purpose in instituting the title "Grand Vizier" was to distinguish the holder of the Sultan's seal from other viziers. The initially more frequently used title of vezir-i âzam (وزیر اعظم) was gradually replaced by sadrazam (صدر اعظم), both meaning "grand vizier" in practice. Throughout Ottoman history, the grand viziers have also been termed sadr-ı âlî (صدر عالی, "high vizier"), vekil-i mutlak (وكیل مطلق, "absolute attorney"), sâhib-i devlet (صاحب دولت, "holder of the State""), serdar-ı ekrem (سردار اكرم), serdar-ı azam (سردار اعظم) and zât-ı âsafî (ذات آصفی, "vizieral person").
Çandarlı Halil Pasha the Elder reformed the role of the vizier in several ways. Several before him held an equivalent but differently named office; he was the first who held the position of “Grand Vizier”, during the reign of Sultan Murad I. He was the first advisor with a military background – his forerunners had come from a more scholarly class of men. It is also significant that he was the first of a political family that, at the time, rivaled the Ottoman dynasty itself. Several of Çandarlı Halil Pasha the Elder’s kin went on to hold the office of Grand Vizier in the decades following his death.