Köprülü family
He was of Abkhazian origin. He was a servant of Köprülü Mehmed Pasha, an able grand vizer who died in 1661. By marrying Köprülü Mehmed Pasha's daughter, he became a relative of the powerful Köprülü family. Together with his brothers-in-law (Köprülüzade Fazıl Ahmed Pasha and Köprülüzade Fazıl Mustafa Pasha), he participated in a number of military campaigns. In 1684, Buda (a part of Budapest, the capital of modern Hungary, then a part of Ottoman Empire) had been besieged by the Austrians under the command of Maximilian. Siyavuş Pasha stormed the Austrians and forced them to lift the siege. This was one of the few Turkish victories in the Great Turkish War.