The Treaty of Bromberg (, Latin: Pacta Bydgostensia) or Treaty of Bydgoszcz was a treaty between John II Casimir Vasa and Elector Frederick William of Brandenburg-Prussia that was ratified at Bromberg (Bydgoszcz) on 6 November 1657. The treaty had several agreements, including the Treaty of Wehlau, signed on 19 September 1657 by the Brandenburg–Prussian and Polish–Lithuanian envoys in Wehlau (Welawa, now Znamensk). Thus, the Treaty of Bromberg is sometimes referred to as treaty of Wehlau-Bromberg or Treaty of Wehlau and Bromberg ().
In exchange for military aid in the Second Northern War and the return of Ermland (Ermeland, Warmia) to Poland, the Polish-Lithuanian monarch granted the Hohenzollern dynasty of Brandenburg hereditary sovereignty in the Duchy of Prussia, pawned Draheim (Drahim) and Elbing (Elbląg) to Brandenburg and handed over Lauenburg and Bütow Land to the Hohenzollerns as a hereditary fief.
The treaty was confirmed and internationally recognized in the Peace of Oliva in 1660. Elbing was kept by Poland, but Lauenburg and Bütow Land and Draheim were later integrated into Brandenburg-Prussia. The sovereignty in Prussia constituted the basis for the later coronation of the Hohenzollern as Prussian kings. Wehlau-Bromberg remained in effect until it was superseded by the (18 September 1773) after the First Partition of Poland. The Treaty of Bromberg later became regarded as one of the worst mistakes in Polish foreign policy towards Prussia after its consequences had become fatal to Poland.Miasta warmińskie w latach 1655-1663 Józef Włodarski Wyższa Szkoła Pedagogiczna w Olsztynie,page 62, 1993
Context
The Duchy of Prussia was established as a Polish fief under duke Albrecht (Albert) in the Treaty of Cracow of 8 April 1525.Jähnig (2006), p. 71 The fief was hereditary, and if Albrecht or his brothers' house became extinct in the male line, the fief was to pass to the Polish king, who was to appoint a German-speaking Prussian-born governor. On 4 June 1563, that provision was changed by King of Poland and Grand Duke of Lithuania Sigismund II Augustus in a privilege issued at Petrikau, which, in addition to Albrecht's branch of the House of Hohenzollern (Hohenzollern-Ansbach), allowed the Brandenburg branch of the Hohenzollern as possible successors.Małłek (2006), p. 75 The privilege provided for the succession of the Brandenburgian electors as Prussian dukes upon the extinction of the House of Hohenzollern-Ansbach in 1618.
In 1656, during the early Second Northern War, the Brandenburgian Hohenzollern took the Prussian duchy and Ermland (Ermeland, Warmia) as Swedish fiefs in the Treaty of Königsberg, before the Swedish king released them from the vassalage and made them absolute sovereigns in those provinces.Vierhaus (1984), p. 169 After fighting along with the Swedish Army in 1656, most prominently at the Battle of Warsaw, Hohenzollern Frederick William I was willing to abandon his ally when the war had turned against them and signalled his willingness to change sides if Polish King and Lithuanian Garnd Duke John II Casimir Vasa would grant him similar privileges as previously Swedish King Charles X Gustav, conditions that were negotiated in Wehlau (Welawa, now Znamensk) and Bromberg (Bygost, Bydgoszcz).Wilson (1998), pp. 36-37
The Polish interest in an alliance with Brandenburg-Prussia was born out of the need to end the war against Sweden as soon as possible.Frost (2004), p. 98 On 3 November 1656, the Truce of Vilna had promised Alexis of Russia's election as a successor on the Polish throne at the next diet in return for halting his offensive in Poland–Lithuania and to fight Sweden instead.Frost (2004), p. 82 In the Grand Duchy of Lithuania, there was support for the treaty from the nobles, who hoped for positions with more privilege, but that was not true for the Kingdom of Poland, where the elites looked for ways to circumvent Alexis's succession.Frost (2004), pp. 86, 89, 98, 103, 128, 132 For a fast end to the war against Sweden to be able to avoid the implementation of the Truce of Vilnius, the anti-Swedish alliance had to be extended.
The newly won Russian ally was reluctant to support Poland against Sweden as long as no diet had confirmed the truce.Frost (2004), p. 86 A second ally, the Austrian Habsburgs, were won in the first and the second Vienna Treaties,Frost (2004), p. 95 but the Habsburg forces were to be maintained by Poland, the prize for the alliance was bound to rise while the war lasted. A third ally was Denmark-Norway, which joined the anti-Swedish coalition in June 1657 after it had been triggered by the second Treaty of Vienna. However, Denmark was not fighting on Polish soil, and although its involvement tied down Charles X Gustav's forces and a formal alliance with Poland was concluded in July, the Danish aimed to recover Scandinavian territories, which had been lost at the Second Treaty of Brömsebro (1645).
The Habsburgs' interest in the treaty was to build up good relations with Frederick William I. As a prince-elector, he was a valuable ally if he supported their policy in the Holy Roman Empire.Frost (2004), p. 97 Thus, the Habsburgs were interested in Frederick William I changing sides and sent diplomat Franz Paul Freiherr von Lisola to mediate a respective settlement.
Bromberg and Wehlau are regarded as "twin treaties",Nolan (2008), p. 334 "supplementary treaties"Stone (2001), p. 169 or one treaty, which is sometimes referred to as "Treaty of Wehlau and Bromberg"Materna (1995), p. 318 or "Treaty of Wehlau-Bromberg."Frost (2004), p. 105
Ratification
The preliminary treaty of Wehlau had been signed on 19 September 1657 by Frederick William I's envoys von Schwerin and von Somnitz, as well as by Warmian (Ermland) prince-bishop and Wincenty Korwin Gosiewski for the Polish–Lithuanian Commonwealth, and Habsburg delegate and mediator Freiherr .Frost (2004), pp. 97, 104Signatories at Wehlau (per Annotated edition, IEG Mainz, retrieved 2010-02-22 ): Venceslaus de Leszno, episcopus Varmien[sis] s[acrae] r[egiae] m[ajesta]tis Poloniae et Sueciae plenipotentiarius Vincentius Corvinus Gosiewski, supremus thesaurarius et campiductor m[agni] d[ucatus] L[ithuaniae] s[acrae] r[egiae] m[ajestatis] Poloniae et Sueciae plenipotentiarius F[ranciscus] De Lisola, seren[issimi] m[ajestatis] Hungariae et Bohemiae regis ad hosce tractatum pro mediatione ablegatus, eiusdemque consiliarius Ottho Liber Baro a Schwerin, plenipotentiarius electoralis Laurentius Christophorus Somnitz, Plenipotentiarius electoralis
The amended and final version of the treaty was ratified on 6 November by Frederick William I and John II Casimir in Bromberg (Bydgoszcz).Biereigel (2005), p. 63The signatories at Bromberg also included Mikołaj Prazmowski and Kazimierz Samuel Kuszewicz. Annotated edition, IEG Mainz. The Brandenburgian elector and the Polish king attended the ceremony with their wives, Luise Henriette of Nassau and Marie Louise Gonzaga, respectively. Danzig (Gdansk) Mayor Adrian von der Linde was also present.van Stekelenburg (1988), p. 255
The Treaties of Wehlau and Bromberg were confirmed by the partiesFrost (2000), p. 183 and internationally recognized at the Peace of Oliva, which ended the Second Northern War in 1660, and by the Polish Sejm in 1659 and 1661.
Agreements The treaty ratified in Bromberg had three parts. The first one contained 22 articlesKamińska (1983), p. 9 and dealt primarily with the status and succession of Prussia, the Brandenburg-Polish alliance, and military aid. It was drafted in Wehlau and signed there by the Brandenburgian and Polish plenipotentiaries and the Habsburg mediator. The second part was a special convention ("Specialis Convention") containing 6 articles, also drafted and signed by the plenipotentiaries and the mediator in Wehlau, which further detailed the alliance and military aid. The third part amended the Wehlau agreement and primarily detailed Polish concessions.Annotated edition, IEG Mainz, retrieved 2010-02-22
Status of Prussia The Duchy of Prussia—where Frederick William I had become fully sovereign by the Brandenburg-Swedish Treaty of Labiau—was likewise accepted by the Polish–Lithuanian Commonwealth to be the sovereign possession of the House of Hohenzollern.Jähnig (2006), p. 68
However, Ermland (Ermeland, Warmia) was to be returned to Poland. And if the Brandenburgian Hohenzollern dynasty became extinct in the male line, the Prussian duchy was agreed to pass on to the Polish crown. That made Prussian estates have to pay conditional allegiance to an envoy of subsequent Polish kings upon their succession (hommagium eventuale, Eventualhuldigung), and they were released from previous oaths and obligations regarding the Polish crown.
The Roman Catholic Church in the former Duchy of Prussia was to remain subordinate to the archbishop of Ermland (Warmia),Kamińska (1983), p. 10 retain its possessions and income and be granted religious freedom.Bahlcke (2008), p. 124
Military aid Brandenburg-Prussia was obliged to give military aid to Polish–Lithuanian Commonwealth against the Swedish Empire during the ongoing Second Northern War.Schmidt (2006), p. 103 Frederick William I had in Wehlau agreed to aid John II Casimir Vasa with 8,000 men,Motsch (2001), p. 85 and both parties agreed on an "eternal alliance".Wilson (1998), p. 36 In Bromberg, it was agreed that from his Prussian province, Frederick William I would dispatch 1,500 foot and 500 horse to join the army of the Polish-Lithuanian monarch.Friedrich (2006), p. 150
Financial and territorial agreements
In return, the Polish crown granted Brandenburg-Prussia Lauenburg and Bütow Land as a hereditary fief. It was to be held under the same conditions as previously granted to the House of Pomerania, free of duties except that the House of Hohenzollern had sent envoys to the coronations of successive Polish-Lithuanian monarchs, who were then to receive a written confirmation of the fief. If the Hohenzollern dynasty had no male heir, the fief should return to the Polish crown.
In addition to Lauenburg and Bütow land, Brandenburg-Prussia was to receive the town of Elbing (Elbląg).Frost (2004), p. 104 In an amendment, Brandenburg-Prussia was obliged to return the town to Poland once the latter had bailed it out with 400,000 thalers.The sum given for the Elbing ransom by historian Robert I. Frost is 40,000 thalers in Frost (2004), p. 104, and 400,000 thalers in Frost (2000), p. 200. It is 300,000 thalers in Oakley (1992), p. 103 and Wilson (1998), p. 135. Kamińska (1983), p. 12 gives 400,000 thalers. The commented edition of the treaty at the Institut für Europäische Geschichte (Institute for European History) in Mainz gives 400,000 reichstalers in the second amendment, overruling Article XII of the Wehlau tractates. Instead of providing 500 horse, Brandenburg-Prussia was to return Elbing and level its fortification upon receiving the payment. Sources given there are: AGADWarschau MK KK Volume 202, p. 40, print: Dogiel IV, p. 497; Pufendorf, p. 389; Dumont VI/2, p. 196; Dolezel, p. 208
The third Polish concession was the payment of 120,000 thalers to Brandenburg-Prussia for war-related damage suffered upon entering the war by Poland. As a security for this payment, the district of Draheim was to be handed over to Brandenburg for three years. The district comprised the town of Tempelburg (now Czaplinek) and 18 villages at the border of Brandenburgian Pomerania.Motsch (2001), p. 18 The sum was to be paid in annual rates of 40,000 thalers, and Brandenburg was to keep Draheim if the money had not been paid by the end of the third year.