They were able to send to the Ægean archipelago another fleet, which blockaded the Dardanelles. In spite of these difficulties, the Turks made an unexpectedly vigorous defence against the Russian invasion in Europe. The campaign of 1828 was mainly one of sieges, where the Turkish soldiers, supported by Moslems of the fortified towns, fought to the best advantage behind walls and earthworks. They could make but a poor stand in the open against their better trained enemy. The Russians, after crossing the Danube, laid siege to Ibrail, the most important fortress on the lower stretch of the river, and which it was essentially necessary to capture before making an advance to Schumla. The garrison and inhabitants made a gallant resistance, and it was only after five weeks that it was compelled to surrender, on June 17th. The Russian army was then divided into three parts—the one to attack Silistria, the capture of which was almost as necessary as that of Ibrail; the second to besiege Varna; the third and most important, under the Emperor, to march to Schumla. The attack on Silistria failed, and after some weeks the force employed against it marched in the direction of Schumla to support the Czar’s army. Even with this addition it was found impossible to invest the fortified camp of the Turks behind Schumla, and, after a demonstration, it was compelled to hold a defensive position, in front of Schumla, while the Czar and a part of the army marched in support of the division before Varna. On August 18th the Czar arrived there with a reinforcement of nine thousand men, and the siege then commenced, while the Russian Black Sea fleet of eight ships of the line and three frigates, under command of Admiral Greig, joined in the attack from the sea. The Turks again made a desperate and prolonged defence, which might have been successful if it had not been that Jussuf Pasha, in command of the garrison, with five thousand of his men, traitorously deserted the city, on October 14th, and threw themselves on the mercy of the Czar. The remainder of the garrison, under the Capitan Pasha, refused to be a party to the surrender. It was said that the cause of this extraordinary act of treachery was that the Sultan, in pursuance of his policy of concentrating all power and authority in himself, had been persuaded by an intrigue to confiscate the property of Jussuf, who was one of the few large landowners in Turkey, while the owner was gallantly fighting the enemy at Varna. However that may be, the remaining garrison was soon compelled to capitulate, and this most important stronghold fell into the hands of the Russians. Without it no advance could possibly have been made across the Balkans.