The fourth Crusade, under Dandolo, when the arms of the Faithful were turned aside from the holy enterprise by the spoils of Constantinople, and the blind Doge leapt from his galleys on the towers of the imperial city, forms the splendid subject of the fourth act. The marvellous spectacle was there exhibited of a band of adventurers, not mustering above twenty thousand combatants, carrying by storm the mighty Queen of the East, subverting the Byzantine empire, and establishing themselves in a durable manner, in feudal sovereignty, over the whole of Greece and European Turkey. The wonderful powers of Gibbon, the luminous pages of Sismondi, have thrown a flood of light on this extraordinary event, and almost brought its principal events before our eyes. The passage of the Dardanelles by the Christian armament; the fears of the warriors at embarking in the mighty enterprise of attacking the imperial city; the imposing aspect of its palaces, domes, and battlements; the sturdy resistance of the Latin squares to the desultory charges of the Byzantine troops; in fine, the storm of the city itself, and overthrow of the empire of the Caesars, stand forth in the most brilliant light in the immortal pages of these two writers. But great and romantic as this event was, it was an episode in the history of the Crusades, it was a diversion of its forces, a deviation from its spirit. It is an ordinary, though highly interesting and eventful siege; very different from the consecration of the forces of Europe to the rescuing of the Holy Sepulchre.