From the beginning of the uprising, Khmelnytsky also appealed to Moscow, which denied giving any military aid to Khmelnytsky for almost six years. Between fall 1648 and spring 1651, Khmelnytsky frequently corresponded with Ottomans, who made vague promises of military aid to the Khmelnytsky. The hetman repeatedly asked the sultan to take him as his subject, but the Ottomans never explicitly acknowledged him as such. The sultan did say that "if the hetman remains faithful", and "‘ahdname", will be granted, meaning that the sultan would guarantee peace and protection. However, by 1653, it became clear to Khmelnytsky that no "‘ahdname" would be granted. Khmelnytsky would show his letters from the sultan to the Muscovite tsar to blackmail him into accepting the hetman into his suzerainty. The Pereyaslav Agreement, signed in March 1654, was a deal to incorporate Ukraine under Russian protection as an autonomous duchy and led to a war between Poland and Muscovy. Despite this treaty, Khmelnystky continued to correspond with the Ottomans in order to pit the Muscovites and the Ottomans against each other. He told each side that they had allied with the other only for tactical reasons.