When Alexander came under the influence of Madame de Krüdener and the more baneful ascendency of Metternich everything was changed for the worse. The publication of Bibles was stopped; the censorship was re-established in its full rigor; Speranski's great undertaking of a Russian code of laws was nipped in the bud; Galytsin, the liberal Minister of Publication, had to resign, and Araktcheyev, a reactionary of extreme type, was put in his place. Some idea of the dark days that followed may be gathered from Araktcheyev's first measures. The teaching of the geological theories of Buffon and of the systems of Copernicus and Newton were forbidden as contrary to Holy Writ. Medical dissection was prohibited, and the practice of medicine was reduced to that of faith cure. All professors who had studied at seats of learning abroad were dismissed. Then it was that the secret societies sprang up in Poland and in the north and south of Russia. One of the foremost conspirators was Pestel, who had undertaken to frame a new code of laws for Russia. When Alexander died, Russia was on the brink of a military revolution. It was the intention of the conspirators to assassinate the Czar in the presence of his troops and to proclaim a constitution; but his unexpected departure to the Black Sea frustrated the plan. Alexander's death threw the Russian court into confusion. For a while it was not known who was to succeed him. The supposed heir to the throne was Alexander's brother, Constantine. Unbeknown to the people he had formally renounced his right to the throne. At the time of his brother's death he was in Warsaw. His younger brother, Nicholas, at St. Petersburg, had him proclaimed emperor. When they brought him Constantine's written abdication, Nicholas refused to acknowledge it and caused the troops to take their oath of allegiance to his brother. Constantine in Warsaw proclaimed Nicholas emperor. Nicholas would not accept the crown unless by the direct command of his elder brother. At length the matter was adjusted, after an interregnum of three weeks. On Christmas Day, Nicholas ascended the imperial throne. The confusion at St. Petersburg was turned to account by the military conspirators who had plotted against Alexander's life. To the common soldiers they denounced Nicholas as a usurper who was trying to make them break their recent oath to Constantine. When ordered to take the oath to Nicholas, the Moscow regiment refused, and marched to the open place in front of the Senate House. There they formed a square and were joined by other bodies of mutineering soldiers. It is gravely asserted by Russian historians that the poor wretches, ignorant of the very meaning of the word constitution, shouted for it, believing it to be the name of Constantine's wife. An attack upon them by the household cavalry was repulsed. When General Miloradovitch, a veteran of fifty-two battles against Napoleon, tried to make himself heard, he was shot. The mutineers would not listen even to the Emperor. Not until evening could the new Czar be brought to use more decisive measures. Then he ordered out the artillery and had them fire grapeshot into the square. The effect was appalling. In a few minutes the square was cleared and the insurrection was over. Its leaders were wanting at the moment of action. A rising in the south of Russia was quelled by a single regiment. Before the year ended, Nicholas was undisputed master of Russia.