Background
He was the son of Gotthard Kettler, the first Duke of Courland. Friedrich Kettler was born to Gotthard Kettler and his wife Anna of Mecklenburg.
He was the son of Gotthard Kettler, the first Duke of Courland. Friedrich Kettler was born to Gotthard Kettler and his wife Anna of Mecklenburg.
The first of two sons, Friedrich in his youth had a good education travelled to many other European countries. After Wilhelm reached majority in 1596, the Duchy was officially partitioned into its Courland and Semigallian parts. During Polish-Swedish War, Duke Friedrich and Wilhelm led their troops in battles against the Swedes, with Friedrich leading 300 big cavalry units in the Battle of Salaspils (1605).
During the war, Courland aristocracy grew in their resistance to the ruling Kettler brothers.
In 1617, the Regional Assembly of Courland (Landtag) sat in Skrunda Castle and decided that Duke Wilhelm be stripped of title and banished from the Duchy. The following year, Friedrich was elected sole Duke of Courland, and he approved a new constitution, Formula Regiminis, which gave greater rights to the aristocracy.
Among the new parameters set by this constitution were that The Duke cannot implement decisions without the prior consent of the Duchy"s council, thus making Courland a constitutional monarchy. In 1622, The Duke"s residence in Jelgava was surrounded by the Swedish army, forcing Friedrich to move to Kuldiga.
Issue
Friedrich Kettler married Elisabeth Magdalena of Pomerania in 1600.
They did not have issue, so in 1625, he proposed that Wilhelm"s son Jacob be recognised as heir. The Duchy"s council agreed to this proposal and Jacob was made co-ruler in 1638.