Köprülü Mehmed Pasha, well informed in the most complicated Ottoman politics, has begun by placing his supporters in key positions and mercilessly repressing opponents and rivals.

The household cavalry Sipahi troops in Istanbul, wanting to put a former leader of the Anatolian mercenaries in power, on January 4, 1657 start a rebellion that Mehmed Pasha cruelly suppresses with the help of janissary troops and the support of the sheikh al-Islam, head of the ulema (scholars trained in Muslim religion and law).

The Greek Orthodox Patriarch of Istanbul is proven to be in treasonous contacts with the enemies of Ottoman state and Mehmed Pasha approves of his execution.