Jacob Kettler

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Jacob Kettler" – news · newspapers · books · scholar · JSTOR (August 2024) (Learn how and when to remove this message)

Jacob Kettler
Portrait of Jacob Kettler, from the Stockholm National Museum
Duke of Courland and Semigallia
Reign	17 August 1642 – 1 January 1682
Predecessor	Frederick Kettler
Successor	Frederick Casimir Kettler
Born	(1610-10-28)28 October 1610 Goldingen (Kuldīga)
Died	1 January 1682(1682-01-01) (aged 71) Mitau (Jelgava)
Burial	Ducal crypt in the Jelgava Palace
Spouse	Margravine Louise Charlotte of Brandenburg ​ ​ (m. 1645; died 1676)​
Issue	Louise Elisabeth, Landgravine of Hesse-Homburg Frederick Casimir Kettler, Duke of Courland Charlotte Sophia, Abbess of Herford Maria Amalia, Landgravine of Hesse-Kassel Charles Jacob Kettler Ferdinand Kettler Alexander Kettler
House	Kettler
Father	Wilhelm Kettler
Mother	Duchess Sophie of Prussia
Religion	Lutheranism

Jacob Kettler (German: Jakob von Kettler; Latvian: Hercogs Jēkabs Ketlers; 28 October 1610 – 1 January 1682) was Duke of Courland and Semigallia from 1642 to 1682. Under his rule, Courland and Semigallia became more independent of its Polish suzerain, reached its peak in wealth, and even engaged in its own overseas colonization, making it one of the smallest, but fastest growing states in the world at that time.

Yet, in the end the results of his rule failed in the confrontation with much stronger powers both directly in the Baltic (Sweden) and overseas (Dutch Republic). A ruler "too rich and powerful to be a duke but too small and poor to be a king"^[1] could not, with his small ancestral territory and very limited resources, play the powerful role he sought in European politics of that time.