Treaty of Vilnius

The Treaty of Vilnius or Vilna was concluded on 28 November 1561, during the Livonian War, between the Livonian Confederation and the Polish-Lithuanian Commonwealth at Vilnius (Vilna, Wilna, Wilno). With the treaty, the non-Danish and non-Swedish part of Livonia, with the exception of the Free imperial city of Riga, subjected itself to Polish king and Grand Duke of Lithuania, Sigismund II Augustus with the Pacta subiectionis (Provisio ducalis). In turn, Sigismund granted protection from the Tsardom of Russia and confirmed the Livonian estates' traditional privileges, laid out in the Privilegium Sigismundi Augusti.

The secularization of the Livonian Order was the "final act" in Livonia's transition from the Middle Ages to the Early Modern era.

The territories were re-organized in the Duchy of Courland and Semigallia and the Duchy of Livonia, the latter competing with the Kingdom of Livonia during the war.

After its reconquest, Sigismund's successor Stephen Báthory (Batory) ignored the privileges of 1561, granted a new constitution and initiated counter-reformation.

These measures were reversed after the Swedish conquest. When after a further series of wars Livonia capitulated to Russia in 1710, the Privilegium Sigismundi Augusti was confirmed by Peter the Great.

n 1513, the Grand Master of the Livonian Order bought his order out of the union with the Teutonic Knights. Thus, the secularization of the Teutonic Order State, which led to the establishment of the Protestant Duchy of Prussia under the Polish king in 1525, did not affect Livonia, where the Recess of Wolmar (Valmiera) forbade any future secularization in 1546.

 The Protestant Reformation had started in Riga in 1517, and afterward it had spread to all of Livonia; religious freedom was declared in 1554.

As the Livonian Confederation was in decline due to internal struggles, a faction of the order favored rapprochement with Poland-Lithuania, while another faction violently opposed it.    After a civil war starting in 1556, the pro-Polish faction gained the upper hand.

With the Treaty of Pozvol, concluded in 1557, the Livonian Confederation had turned to Poland-Lithuania for protection, triggering Ivan IV of Russia's intervention in what was to become the Livonian War.

 In 1558, Ivan IV had conquered the Dorpat (Tartu) area, annihilating theBishopric of Dorpat.

 With the Treaty of Vilnius of 31 August 1559, Gotthard von Kettler, Grand Master of the Livonian Order, had put the order's lands under protection of Polish king and Grand Duke of Lithuania, Sigismund II Augustus. The order ceded about one seventh of its territory, allowed Sigismund to garrison its most important castles, and agreed to share with him any conquests made from Ivan IV.

The alliance was intended to neutralize the imminent threat of annexation of the order's lands by Russia, yet despite earning military support from Polish-Lithuanian chancellor Mikołaj "the Black" Radziwiłł, Kettler was defeated in Ergeme (Ermes, 1560) and unable to prevent the occupation of most of Livonia by Russian forces.

 After the treaty, the disintegrating order agreed to secularization if necessary, and since Sigismund was reluctant to support it militarily, continued its search for a protector at the courts of Denmark-Norway and the Holy Roman Emperor.

In 1560, Johann von Münchhausen sold his bishoprics of Ösel-Wiek and Courland to Magnus, brother of Danish king Frederick II.

 In June 1561, part of Estonia subordinated itself to Sweden.

 Riga had turned to the Holy Roman Empire and became a Free imperial city

Hard-pressed by Ivan IV of Russia, the remnant of the Livonian Confederation concluded a treaty with Poland-Lithuania on 28 November 1561, subordinating themselves to the Sigismund II Augustus.

Consequences

In the Duchy of Courland and Semigallia, a stable political system was established on the basis of the 1561 treaty, and only in 1617 this was modified by the Formula regiminis and Statuta Curlandiæ, which granted the indigenous nobles additional rights at the duke's expense.

Duchy of Courland kept its rughts more than 230 years- up to 1795, when after the 3rd division of Poland, was occupied and annected by Russian Empire. Due historical ties with Poland, Courland was conquered by Napoleon Army in 1812 in some weeks.

All the Polish uprisings (1831, 1863 etc.)  against Russian Empire were supported by Latvians, esspecialy strong support was in Latgale (former Duchy of Livonia) districts