Frederick William (German: Friedrich Wilhelm; 19 July 1692 – 21 January 1711) was Duke of Courland and Semigallia from 1698 to 1711. Frederick Wilhelm was the son of Frederick Casimir Kettler and Elisabeth Sophie of Brandenburg. During his reign the duchy was occupied by Swedish and later by Russian troops.

Friedrich Wilhelm Kettler was born in 1692 in Jelgava in the family of Friedrich Casimir and his second wife Elizabeth Sophia. At the age of seven, after his father's death, in the 22 January 1698 he was appointed as the Duke of Courland and Semigallia, however, until the age of majority state was governed by his mother and uncle Ferdinand Kettler, who resided in Danzig.

When in the 1701 Semigallia was occupied by the Swedes, Friedrich Wilhelm with her mother went to his uncle Prussian Friedrich, who later was crowned the first king of Prussia. He stayed in Prussia until 1709 when after Russian victories against Sweden was decided to engage marriage between 17 years old Friedrich Wilhelm and Anna, daughter of Tsar Ivan V who himself was half brother of Peter the Great. Council of the Duchy in the 1709 recognized Friedrich Wilhelm adult and the young Duke arrived in the Liepaja in 1710.

On 11 November 1710 (31 October, after the old style) a grand wedding was held in the new Russian capital St. Petersburg, which presented the power of the emerging Russian empire and its court brilliance. However on the way back from St. Petersburg, Friedrich Wilhelm died on 21 January 1711 in the postal station, and his widow Anna, together with the Duke's corpse arrived in Jelgava only on 4 March. After his death, the Duchy passed to Ferdinand Kettler, but was de facto controlled by Russia. It was restored to independence in 1737, when it passed to the lover of Tsarina Anna, Ernst Johann Biron.

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