In the spring of 1678, the Turks again entered the Ukraine with a still more formidable army than the year before. The campaign was opened by laying siege to the city Czeherin, which was encompassed by nearly four hundred thousand men, and, after a destructive cannonade, was carried by storm. The garrison, consisting of thirty thousand men, were put to the sword. The Russian troops were so panic-stricken by this defeat, that they speedily retreated. The Turks pursued them a long distance, constantly harassing their rear. But the Turks, in their turn, were compelled to retire, being driven back by famine, a foe against whom their weapons could make no impression. The Ottoman Porte soon found that little was gained by waging war with an empire so vast and sparsely settled as Russia, and that their conquest of the desolated and depopulated lands of the Ukraine, was by no means worth the expenses of the war. The Porte was therefore inclined to make peace with Russia, that the Turkish armies might fall upon Poland again, which presented a much more inviting field of conquest. The Poles were informed of this through their embassador at Constantinople, and earnestly appealed to the tzar of Russia, and to all the princes in Christendom to come to their aid. The selfishness which every court manifested is humiliating to human nature. Each court seemed only to think of its own aggrandizement. Feodor consented to aid them only on condition that the Poles should renounce all pretension to any places then in possession of Russia. To this the Polish king assented, and the armies of Russia and Poland were again combined to repel the Turks. CHAPTER XVIII. THE REGENCY OF SOPHIA. From 1680 to 1697. Administration of Feodor.--Death of Feodor.--Incapacity of Ivan.--Succession of Peter.--Usurpation of Sophia.--Insurrection of the Strelitzes.--Massacre in Moscow.--Success of the Insurrection.--Ivan and Peter Declared Sovereigns under the Regency of Sophia.--General Discontent.--Conspiracy against Sophia.--Her Flight to the Convent.--The Conspiracy Quelled.--New Conspiracy.--Energy of Peter.--He Assumes the Crown.--Sophia Banished to a Convent.--Commencement of the Reign of Peter. Feodor, influenced by the wise counsels of his father, devoted much attention to the beautifying of his capital, and to developing the internal resources of the empire. He paved the streets of Moscow, erected several large buildings of stone in place of the old wooden structures. Commerce and arts were patronized, he even loaning, from the public treasury, sums of money to enterprising men to encourage them in their industrial enterprises. Foreigners of distinction, both scholars and artisans, were invited to take up their residence in the empire. The tzar was particularly fond of fine horses, and was very successful in improving, by importations, the breed in Russia.