Duchy of Estonia (1561–1721)

The Duchy of Estonia (Swedish: Hertigdömet Estland; Estonian: Eestimaa hertsogkond; German: Herzogtum Estland), also known as Swedish Estonia (Swedish: Svenska Estland), was a dominion of the Swedish Empire from 1561 until 1721 during the time that most or all of Estonia was under Swedish rule. The territory was eventually ceded to Russia in the Treaty of Nystad, following its capitulation during a plague outbreak in the Great Northern War.

Source: Wikipedia — Duchy of Estonia (1561–1721) (CC BY-SA 4.0)