This was brought home to him in 1832, when trouble broke out between Turkey and Egypt. The Egyptian army was victorious and threatened Constantinople, when the sultan appealed to the powers. Russia responded at once by sending two armies, but a strong protest from England and France caused the withdrawal of the troops of Russia as well as those of Egypt. Baffled, Nicholas on June 3, 1833, entered into an offensive-defensive alliance with the sultan, which really placed Turkey and with it Constantinople in Russia's power. Another sharp protest from England and France prevented the consummation of the alliance. In 1839 the trouble between Turkey and Egypt recommenced when Great Britain, anxious to preserve Turkey's integrity, entered into an agreement with Russia, Austria and Prussia, which was signed at London in July, 1840. There was some danger of a war with France but England, fearing Russia's designs, returned to her former ally. By the Convention of July 13, 1841, Russia's designs upon old Czargrad were postponed until a more favorable opportunity. In 1844, Nicholas visited England, but his reception in London was cool. He, however, entered into an agreement whereby the Khanates of Central Asia should remain neutral ground between Russia and India. In 1846, trouble broke out in Gallicia, where the Poles rose against Austria; but as the nobles had to subdue a revolt of their own (p. 213) peasants, order was quickly restored. The free city Cracow was the resort of the Poles. Russia, Austria, and Prussia sent troops against it, and Cracow was annexed by Austria notwithstanding a protest from England and France. The year 1848 will long be remembered for the blows bestowed upon the divine right of kings, and the privileges which the sovereigns were compelled to concede to the people. The Emperor Ferdinand of Austria was expelled from his capital, and the King of Prussia was subjected to humiliation by his own people. France proclaimed the republic, and Nicholas proclaimed himself the champion of the right divine. He dispatched an army into Hungary, which was soon "at the feet of your Majesty," and felt the wrath of the frightened Ferdinand. Notwithstanding this cooperation, the understanding among the three powers, Russia, Austria and Prussia, was giving way before individual interests. When, in 1852, Prussia attempted to seize the German provinces of Denmark, it was Nicholas who compelled her to withdraw. On the 8th of May of that year, the independence and integrity of Denmark were recognized by the Treaty of London.