Treaty of Wehlau

The Treaty of Wehlau ( _de. Vertrag von Wehlau; _pl. Traktat Welawski) was a treaty signed in the eastern Prussian town of Wehlau ("Welawa", now "Znamensk") between Poland and Brandenburg-Prussia during the Swedish Deluge on September 19, 1657.

In his capacity as Duke of Prussia, Margrave Frederick William, the "Great Prince-elector" of Brandenburg, had revoked his oath of loyalty to his sovereign King John II Casimir of Poland in 1656 and allied against him with King Charles X Gustav of Sweden, whom Frederick William recognized as sovereign over Prussia. In the Treaty of Labiau later that year Charles granted the margrave sovereignty over Prussia and Warmia. After his defeat in the Battle of Warsaw in 1656, John Casimir met with Frederick William at Wehlau. In return for the margrave's renunciation of the Brandenburg-Sweden alliance, the Polish king recognized Frederick William's full sovereignty over the Duchy of Prussia, which was since the Second Peace of Thorn (1466) a Polish and also briefly a Swedish fief. In case Brandenburg-Prussia's Hohenzollern dynasty died out, Duchy of Prussia was to return to the crown of Poland.

Johann von Hoverbeck was one of the Brandenburg-Prussian diplomats during the negotiations of this treaty. The treaty was amended by the Treaty of Bromberg ("Bydgoszcz") of 6 November 1657 and confirmed by the Treaty of Oliva in 1660.

The treaty was to be reconfirmed every time a new ruler of either Prussia or Poland succeeded (though this did not always happen immediately). This happened on the following occasions:

* 1672: Accession of Michał Korybut Wiśniowiecki as King of Poland 1669.
* 1677: Accession of John III Sobieski as King of Poland 1674.
* 1688: Accession of Frederick I of Prussia as Duke of Prussia 1688.
* 1698: Accession of Augustus II the Strong as King of Poland 1697.

Because Hohenzollern sovereignty in Prussia lay outside of the Holy Roman Empire, Elector Frederick III was able to elevate the Duchy of Prussia to the Kingdom of Prussia in 1701, at which point the treaty was considered nullified and was no longer renewed.

ee also

*List of treaties
*Treaty of Bydgoszcz
*Treaty of Oliva