Towards the end of the seventeenth century ecclesiastical corruption in the Orthodox Church increased. Bishoprics, and even the patriarchate were sold to the highest bidder. The Turks displayed their contempt for them by ordering the cross which until that time had crowned the dome of the belfry of the patriarchate to be taken down. There can be no doubt, however, that in the rural district the secular clergy supplied some of the moral strength which eventually enabled the Greeks successfully to resist the Othoman power. Happily, the exaction of the tribute of children fell into disuse; and, that burden removed, the nation soon began to fed the possibility of improving its condition. The contempt with which the ambassadors of the Christian powers were treated at the Sublime Porte increased after the conquest of Candia and the surrender of Crete in 1669, and the grand vizier, Kara Mustapha, declared war against Austria and laid siege to Vienna in 1683. This was the opportune moment taken by the Venetian Republic to declare war against the Othoman Empire, and Greece was made the chief field of military operations. Morosini, the commander of the Venetian mercenary army, successfully conducted a series of campaigns between 1684 and 1687, but with terrible barbarity on both sides. The Venetian fleet entered the Piraeus on September 21, 1687. The city of Athens was immediately occupied by their army, and siege laid to the Acropolis. On September 25 a Venetian bomb blew up a powder magazine in the Propylæa, and the following evening another fell in the Parthenon. The classic temple was partially ruined; much of the sculpture which had retained its inimitable excellence from the days of Phidæas was defaced, and a part utterly destroyed. The Turks persisted in defending the place until September 28, when, they capitulated. The Venetians continued the campaign until the greater part of Northern Greece submitted to their authority, and peace was declared in 1696. During the Venetian occupation of Greece through the ravages of war, oppressive taxation, and pestilence, the Greek inhabitants decreased from 300,000 to about 100,000. Sultan Achmet III., having checkmated Peter the Great in his attempt to march to the conquest of Constantinople, assembled a large army at Adrianople under the command of Ali Cumurgi, which expelled the Venetians from Greece before the end of 1715. Peace was concluded, by the Treaty of Passarovitz, in July 1718. Thereafter, the material and political position of the Greek nation began to exhibit many signs of improvement, and the agricultural population before the end of the eighteenth century became, in the greatest part of the country, the legal as well as the real proprietors of the soil, which made them feel the moral sentiment of freemen.