Whatever the cause or the combination of causes—and the history of these tracts remains very obscure—the results were the retreat southwards of the cultivated area, with the consequence that, after over 1,000 years of Mohammedan rule, Egypt found herself in the weakened and impoverished condition already described; saved only from annihilation by the system of basin irrigation, of which the traditions survived, though in a diminished area, stubbornly preserved from age to age by her industrious and conservative peasantry. CHAPTER III PERENNIAL IRRIGATION It was the Viceroy Mehemet Ali who revolutionized the methods of Egyptian agriculture, and introduced what is known as perennial irrigation—that is to say, irrigation all the year round, as opposed to irrigation during the flood only. In all the annals of the East there are few more striking figures and few histories more exciting than that of the Albanian tobacco-seller, who, rising high in the favour of Sultan Mahmoud, was sent to Egypt as Viceroy in 1810. Adopting a method well known in Cairo, and well calculated to secure the respect, and even the affection, of Orientals, he consolidated his power by the treacherous murder of the Mamelukes, and thoroughly organized the military resources of his province. Summoned to the aid of the Sultan, his armies bloodily stamped out the successful rising of the Greeks in the Peloponnese, and left to himself he would have settled the question of Greek independence once for all. But his summary proposal to transport the whole Christian population, and repeople the Morea with Mohammedan plantations, provoked the intervention of the Powers, and at Navarino he suffered the complete loss of his fleet. Undismayed, he conceived the idea of making himself master of the Turkish Empire. His armies overran Syria, and easily overcoming the Turkish opposition, he threatened Constantinople itself. Once more, if left to himself, he would have succeeded in his object, but once more the slow processes of European diplomacy at last resulted in action. British guns gave the death-blow to his hopes at Acre, and Turkey was saved from her ambitious vassal, though Egypt remained a practically independent State, and her sovereignty became the hereditary appanage of the house of Mehemet.