Grand Vizier
The Ottoman sultan's all-powerful deputy, who ran the empire day to day and was executed for its failures often enough to make the job lethal.
The grand vizier was the second most powerful person in the Ottoman Empire and, for long stretches, the most powerful in practice. He held the imperial seal, presided over the council of state, commanded armies in the sultan's name, appointed and dismissed officials, and signed treaties. When European diplomats spoke of negotiating with the Sublime Porte, they meant his gate, not the sultan's. The office is the key to how an empire of tens of millions was actually administered, and to why its later sultans could be nonentities without the state immediately falling over.
Absolute power, borrowed
The grand vizier's authority was total and entirely derived. Everything he did, he did as the sultan's deputy, holding the mühr-ü hümayun, the imperial seal, as the physical token of that delegation. Handing the seal over was the appointment ceremony. Taking it back was the dismissal, and dismissal frequently came with a bowstring.
That combination, unlimited authority and zero security, is the office's defining feature. Suleiman the Magnificent had his closest friend and grand vizier Ibrahim Pasha strangled in the palace in 1536 after thirteen years of extraordinary service, apparently because Ibrahim had become too visible. Kara Mustafa Pasha, who led the failed siege of Vienna in 1683, was executed in Belgrade that December and his head sent to Istanbul. In some periods of crisis grand viziers lasted months. The state got a chief executive who could act without consulting anyone and who knew that failure was capital.
Many of them were not born Muslim and not born Ottoman. The devshirme system took Christian boys from the Balkans, the same pipeline that filled the Janissary corps, converted and trained them, and the best rose through the palace school into the highest offices of the empire. A slave-origin Albanian, Bosnian, or Greek could end up running an empire from the Danube to the Nile, precisely because he had no independent family power base and owed everything to the sultan. Merit and dependence were designed into the same system.
When the vizier became the state
The office grew as the sultanate shrank. The early sultans led armies personally and governed personally. After Suleiman, princes were raised in the palace rather than in provincial governorships, and many sultans came to the throne with no administrative experience and little inclination. The machinery kept running because the grand vizier ran it.
The clearest case is the Köprülü era. In 1656, with the empire in fiscal crisis and losing a naval war to Venice, the elderly Albanian Mehmed Köprülü accepted the grand vizierate on written conditions: total freedom of action and no interference from the palace or the harem. He got it, purged the administration, and stabilized the state. His son, nephew, and other relatives held the office for most of the next fifty years and led an Ottoman recovery that reached the walls of Vienna. It was the most effective government the empire had since Suleiman, and no sultan directed it.
By the nineteenth century the Sublime Porte had become an institution in its own right, with a foreign ministry, a bureaucracy, and a reformist tradition. The Tanzimat reforms were driven from the Porte, and the reforming statesmen of that era were the empire's real rulers for decades. When the Young Turks eventually seized control in 1908 and after, they were fighting over this apparatus, not the throne.
Why it matters
The grand vizierate is the answer to a question that puzzles readers of Ottoman history: how did an empire that produced a long line of weak and sometimes deranged sultans keep functioning for another three hundred years? Because sovereignty and administration had been formally separated. The sultan was legitimacy. The Porte was government.
The cost of that arrangement was that no institution could ever consolidate against the palace, since any minister strong enough to matter could be executed at will. The empire got flexibility and lost continuity. Reform programs died with their authors, and no Ottoman equivalent of a permanent cabinet or an independent judiciary could grow in soil where the chief minister might be strangled for losing a battle. That is a general trap for personalist regimes, and the Ottomans ran the longest experiment in it.