The Duchy of Courland was a historical territory located in present-day Latvia and Lithuania. It existed from the early 16th century until the late 18th century and was a vassal state of the Polish-Lithuanian Commonwealth. The duchy was known for its maritime trade and naval power, particularly during the reign of Duke Jacob Kettler. Courland's economy thrived on agriculture, fishing, and trade, with its capital in Jelgava. The duchy also established colonies in the Caribbean and North America, notably the island of Saint Andrew. In 1795, the duchy was annexed by the Russian Empire, marking the end of its autonomy.