Frederick I. (Wilhelm Karl), first king of Wurtemberg, son of the duke Frederick Eugene, born at Treptow, Pomerania, Nov. 6, 1754, died Oct. 30, 1816. He received his first instruction from his accomplished mother, a princess of Brandenburg-Schwedt, and completed his education at Lausanne, after the French fashion of that period, served in the bloodless war of the Bavarian succession, accompanied his brother-in-law, the future Russian emperor Paul, on a journey to Italy in 1782, was made governor general of Russian Finland, and after having left it in 1787 lived for some time in retirement. In 1790 he was a spectator of the sessions of the French national assembly; in 1796 he fought against the French on the Rhine, and in the following year he succeeded his father on the ducal throne. He shared in the war of 1799, received by the treaty of Luneville ample indemnity for territories lost on the left bank of the Rhine, and was allowed to assume the electoral dignity. In 1805 he made an alliance with Napoleon, joined the Rhenish confederation, and received from its protector the title of king. He deserted Napoleon after his disasters. The treaty of Vienna left him in possession of his kingdom.

To conciliate his people after ten years of despotic sway, he gave them a charter, which was rejected by the estates. A new constitution was drawn up, but he died before it could be discussed. His first wife was a princess of Brunswick-Wolfenbiit-tel, who bore him two sons, William, his successor, and Paul, and a daughter, Catharine, afterward princess of Montfort. His second wife was the princess Charlotte Augusta Matilda of England, who died in 1828.