While Peter was thus engaged in winding the chains of despotism more tightly round the necks of his subjects at home, he was equally busy in trying to extend the frontiers of Russia to the sea, at the expense of his neighbours abroad. No one could doubt that the first essential of the due development of Russia was to obtain a footing upon the Baltic. The port of Archangel on the frozen White Sea, and the port of Azof on the Black Sea, closed as it was to the trade of the Mediterranean by the straits of the Bosphorus and the Dardanelles in the hands of the Turks, were not sufficient to enable Russia to expand into a commercial nation. But since the treaties of Stolbovo and Kardis, renewed as late as 1684 by the princess Sophia, Russia had acquiesced in the annexation of the Baltic lands by Sweden, and it was certain that Sweden would not tamely surrender her treaty rights. But in the year 1697 an opportunity offered, which was too tempting for Peter’s slender stock of virtue to resist. [Sidenote: =Coalition against Sweden, 1699.=] Charles XI. of Sweden died, leaving as his heir and successor his youthful son Charles XII., only fifteen years of age. Patkul, a nobleman of Livonia, who was eager to restore the independence of his country, applied to Denmark, Poland, and Russia, the hereditary enemies of Sweden, for assistance. Each power, thinking only of its own aggrandisement, caught willingly at the chance of crushing Sweden when she was weak, and in 1699 this nefarious alliance was concluded, in which the independence of Livonia was used merely to cloak a policy of pure aggression. [Sidenote: =Defeat of the allies by Charles XII.=]