John Albert II, Duke of Mecklenburg

John Albert II, Duke of Mecklenburg
Portrait of John Albert II from the year 1635 (National Museum, Warsaw)
Spouse(s)	Margaret Elizabeth of Mecklenburg Elizabeth of Hesse-Kassel Eleonore Marie of Anhalt-Bernburg
Noble family	House of Mecklenburg
Father	John VII, Duke of Mecklenburg
Mother	Sophia of Schleswig-Holstein-Gottorp
Born	(1590-05-05)5 May 1590 Waren
Died	23 April 1636(1636-04-23) (aged 45) Güstrow

John Albert II, Duke of Mecklenburg[-Güstrow] (5 May 1590 in Waren – 23 April 1636 in Güstrow) was a Duke of Mecklenburg. From 1608 to 1611, he was the nominal ruler of Mecklenburg-Schwerin; the actual ruler being the regent, his great-uncle Charles I. From 1611 to 1621 John Albert and his brother Adolf Frederick I jointly ruled the whole Duchy of Mecklenburg. From 1621, John Albert ruled Mecklenburg-Güstrow alone.

John Albert was the son of Duke John VII and Sophia of Schleswig-Holstein-Gottorp.

He reigned from 16 April 1608, under the regency of his great-uncle Duke Charles I, jointly with his brother Adolf Frederick I in the Mecklenburg-Schwerin part of the country. After Charles's death, the Emperor declared Adolf Frederick an adult and he ruled alone until John Albert came of age and they began to rule jointly.

In 1617 he converted to Protestantism. In the division of Mecklenburg of 1621, John Albert received Mecklenburg-Güstrow.

In 1623, both brothers joined a defensive alliance of the Lower Saxon Estates. They tried to seem neutral during the Thirty Years' War, but they secretly supported the Danish troops of king Christian IV. After the Imperial side won the Battle of Lutter, Tilly treated them as enemies. On 19 January 1628, Emperor Ferdinand II issue a decree at Brandýs Castle declaring that the brothers had forfeited their fief and that Mecklenburg would be invested to Wallenstein. In May 1628, the brothers left the Duchy, at the request of Wallenstein. In May 1631, Wallenstein was overthrown by Swedish troops, and the brothers returned.