On 4th November 1666, Fazil Ahmet Kiopruli, Grand Vizier of the Ottoman Empire, landed on Crete at the head of massive reinforcements. As attacks grew in intensity, casualties on both sides were frighteningly high. The defenders' predicament worsened from November 1667 onwards, as the Turks concentrated their offensive on the weakest points in the enceinte. Their information was obtained from Colonel Andrea Barozzi, a deserter thenceforth branded as the betrayer of Chandax.
On seeing the disagreements dividing the Christian camp, and realizing that further resistance was impossible, Francsico Morosini, the Venetian commander-in-chief, decided to enter into peace negotiations. The final treaty was signed on 16th September 1669, bringing an end to centuries of Venetian dominion over the island, with the exception of the small seaward strongholds at Gramvousa, Suda and Spinalonga.