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.

Nicholas had scarcely been crowned (1826) when war broke out between Russia and Persia; and this was followed by war with Turkey, consequent upon the Greek revolution.  Silistria, a great fortress in Bulgaria, fell into the hands of the Russians, who pushed their way across the Balkan mountains and occupied Adrianople.  In the meantime General Paskievitch followed up his brilliant successes in the Asiatic provinces of the Sultan’s dominions by the capture of Erzeroum, and advanced to Trebizond.  The peace of Adrianople, in September, 1829, checked his farther advances.  This famous treaty secured to the Russians extensive territories on the Black Sea, together with its navigation by Russian vessels, and the free passage of Russian ships through the Dardanelles and Bosphorus to the Mediterranean.  In addition, a large war indemnity was granted by Turkey, and the occupancy of Moldavia, Wallachia, and Silistria until the indemnity should be paid.  Moreover, it was agreed that the hospodars of the principalities should be elected for life, to rule without molestation from the Porte upon paying a trilling tribute.  A still greater advantage was gained by Russia in the surrender by Turkey of everything on the left bank of the Danube,—­cities, fortresses, and lands, all with the view to their future annexation to Russia.

The territory ceded to Russia by the peace of Adrianople included the Caucasus,—­a mountainous region inhabited by several independent races, among which were the Circassians, who acknowledged allegiance neither to Turkey nor Russia.  Nicholas at first attempted to gain over the chieftains of these different nations or tribes by bribes, pensions, decorations, and military appointments.  He finally was obliged to resort to arms, but without complete success.