Selim fell completely under the influence of his Grand Vizier, who had held the post for two years under Solyman. Sokolli, who was a most capable man, was the virtual ruler of the Empire. He was a man of large views. He had two important and interesting schemes in his mind. The one to cut a canal across the Isthmus of Suez, so that the Turkish fleet might find its way into the Red Sea and Indian Ocean, the other to make a junction by a canal between the rivers Don and Volga. These two great rivers, which have their sources in Russia, run a parallel course for a long distance, and at one point approach one another within thirty miles. They then diverge again, the one flowing into the Sea of Azoff, the other into the Caspian Sea. By joining these two rivers by a canal at the point where the distance between them is the least, it would be possible for a Turkish flotilla to ascend the Don, and then, after passing through the canal, descend the Volga into the Caspian Sea, whence it would be able to attack the Persian province of Tabriz with great advantage. The commercial possibilities of this junction of the two great water highways were also obvious. The scheme, however, necessitated taking Astrakan and other territory from Russia—a country which had of late years largely extended its possessions and power. In this view, Sokolli, in 1568, sent an army of twenty-five thousand Janissaries and Spahis by sea to Azoff. They were there joined by thirty thousand Tartars from the Crimea, and the combined force marched thence to Astrakan, at the mouth of the Volga. For the first time, therefore, the Ottomans came into direct conflict with the Russians. The expedition was a total failure. The Turks were unable to capture Astrakan, and a Russian army completely destroyed that of the Tartars. The main Turkish army was compelled to retreat to Azoff. Later, the greater part of it was lost in a great tempest in the Black Sea, and only seven thousand of its men returned to Constantinople. The project of a Don and Volga canal was consequently abandoned. That for a canal across the Isthmus of Suez was also indefinitely adjourned, owing to an outbreak of the Arabs in the province of Yemen, which necessitated sending an army there under Sinan Pasha. This was thoroughly successful, and Yemen and other parts of Arabia were completely and finally brought under the subjection of the Ottoman Empire.