FREDERICK I. (1657-1713), first king of Prussia, and (as Frederick III.) elector of Brandenburg, was the second son of the great elector, Frederick William, by his first marriage with Louise Henriette of Orange. Born at Konigsberg on July 11, 1657, he was educated and greatly influenced by Eberhard Danckelmann, and became heir to the throne of Brandenburg through the death of his elder brother, Charles Emil, in 1674. He appears to have taken some part in public business before his father's death; and the court at Berlin was disturbed by quarrels between the young prince and his stepmother, Dorothea of Holstein-G1iicksburg. In 1686 Dorothea persuaded her husband to bequeath outlying portions of his lands to her four sons ; and Frederick, fearing he would be poisoned, left Brandenburg determined to prevent any diminution of his inheritance. By promising to restore Schwiebus to Silesia after his accession he won the support of the emperor Leopold I. ; but eventually he gained his end in a peace able fashion. After he became elector of Brandenburg in May 1688, his half-brothers renounced their rights under their father's will in return for a sum of money, and the new elector thus se cured the whole of Frederick William's territories. He fulfilled his bargain with Leopold and gave up Schwiebus in 1695. At home and abroad Frederick continued the policy of the great elector. He helped William of Orange to make his descent on England; added various places, including Bonn, Quedlinburg, the princi pality of Neuchatel, to his lands; and placed his large and efficient army at the disposal of the emperor and his allies (see BRANDEN BURG). He was present in person at the siege of Bonn in 1689, but was not often in command of his troops. The elector sought to model his court upon that of Louis XIV., and directed his main energies towards obtaining for himself the title of king. He gave Leopold, in return for a promise of military aid, the imperial sanction to Frederick's request in November 17oo; and the elec tor, hurrying at once to Konigsberg, crowned himself king of Prussia on Jan. 18, 1701. During the War of the Spanish Succes sion the troops of Brandenburg-Prussia rendered great assistance to the allies at Blenheim and elsewhere. Frederick, who was de formed through an injury to his spine, died Feb. 25, 1713. He founded the university of Halle, and the Academy of Sciences at Berlin; welcomed and protected Protestant refugees from France and elsewhere; and lavished money on the erection of public buildings. The king was married three times. His second wife, Sophie Charlotte (1668-1705), sister of the English king George I., was the friend of Leibnitz and one of the most cultured prin cesses of the age; she bore him his only son, his successor, King Frederick William I.
See W. Hahn, Friedrich I., Konig in Preussen (Berlin, 1876) ; J. G. Droysen, Geschichte der preussischen Politik, Band iv. (Leipzig, 1872) ; E. Heyck, Friedrich I. and die Begriindung des preussischen Konigtums (Bielefeld, 19o1) ; Arcs dem Briefwechsel Konig Friedrichs I. von Preussen and seiner Familie, ed. Berner (Berlin, Igoe) ; H. von Hymmen, Der erste preussische Konig (1904).