Alexander was twenty-four when, in 1801, he became the autocrat of all the Russias. His reign is familiar to all the readers of the wars of Napoleon, during which Russia settled down as one of the great Powers. At the Congress of Vienna in 1814 the duchy of Warsaw, comprising four-fifths of the ancient kingdom of Poland, was assigned to Russia. During fifty years Russia had been gaining possession of new territory,--of the Crimea in 1783, of Georgia in 1785, of Bessarabia and a part of Moldavia in 1812. Alexander added to the empire several of the tribes of the Caucasus, Finland, and large territories ceded by Persia. After the fall of Napoleon, Alexander did little to increase the boundaries of his empire, confining himself, with Austria and Prussia, to the suppression of revolutionary principles in Europe, the weakening of Turkey, and the extension of Russian influence in Persia. In the internal government of his empire he introduced many salutary changes, especially in the early part of his reign; but after Napoleon's final defeat, his views gradually changed. The burdens of absolute government, disappointments, the alienation of friends, and the bitter experiences which all sovereigns must learn soured his temper, which was naturally amiable, and made him a prey to terror and despondency. No longer was he the frank, generous, chivalrous, and magnanimous prince who had called out general admiration, but a disappointed, suspicious, terrified, and prematurely old man, flying from one part of his dominions to another, as if to avoid the assassin's dagger. He died in 1825, and was succeeded by his brother,--the Grand Duke Nicholas. The throne, on the principles of legitimacy, properly belonged to his elder brother,--the Grand Duke Constantine. Whether this prince shrank from the burdens of governing a vast empire, or felt an incapacity for its duties, or preferred the post he occupied as Viceroy of Poland or the pleasures of domestic life with a wife to whom he was devoted, it is not clear; it is only certain that he had in the lifetime of the late emperor voluntarily renounced his claim to the throne, and Alexander had left a will appointing Nicholas as his successor.