His father dying in 1640, the young prince found his dominions reduced to a most deplorable condition by war and bad government. The exactions of Wallenstein in Altmark alone were estimated at twenty millions of gold florins; and in a memorial of the magistrate of Prenzlau, it is stated that the inhabitants are reduced to such dreadful extremities that they not only eat dogs, cats, and even carrion, but that, both in the town and country, they attack and kill each other for food. He commenced his government with a degree of prudence and wisdom rarely found in so young a sovereign. His first care was to correct many crying abuses and to restore order in the finances. His attention was then directed to foreign affairs. In 1642 he received the investiture of Prussia from the King of Poland; in 1643 he concluded a peace with the Swedes, on condition of their evacuating the greater part of his dominions. At the peace of Munster he was not able to enforce his claims to Pomerania and Silesia, but obtained Magdeburg, Wallenstadt, Minden, and part of Pomerania. It is highly to his credit that it was chiefly owing to him, that the principle of equal rights and privileges for the two great divisions of the Protestant Church was admitted in that famous treaty. Charles Gustavus, King of Sweden, appearing emulous of rivalling Gustavus Adolphus, the elector concluded an alliance with Holland, and sought the friendship of Cromwell and Louis XIV. He was, however, obliged to make in 1655 a treaty with the Swedes, in consequence of which he joined in the invasion of Poland, and greatly contributed to the victory at Warsaw. Austria, Holland, and Poland vehemently protested against this alliance with Sweden. Cromwell, however, who believed the Protestant cause to be in danger from the King of Poland, sent William Jepson as his ambassador to the elector, whom in letters he compliments in the highest terms for his service to the Protestant religion. But Russia and Austria declaring in favor of Poland, he, by the mediation of Austria, concluded a convention with Poland at Wehlau, by one of the stipulations of which he obtained the entire sovereignty of Prussia, and in 1678 completed the conquest of all Pomerania by the taking of Griefswald and Stralsund. The death of Charles Gustavus freed him from an adversary who would probably have endeavored to prevent the execution of this treaty, which was confirmed by the treaty of Oliva. Frederick, now at peace with his neighbors, directed all his attention to promote the welfare of his subjects by favoring all internal improvements; the ruined towns and villages were rebuilt, new roads made, waste lands cultivated, commerce encouraged, and many useful establishments founded. [Illustration: The Great Elector withdraws from the association of the Dutch nobility.]