War of the Polish Succession (1817–25)

The War of the Polish Succession or the British-Polish War took place from 1814 to 1815 over the election of monarch after the death of King of the Polish James Casimir I. The war was fought between factions of Stanislaus III Albert and High Lord Admiral and Duke William Henry, the future William IV, with Stanislaus eventually being crowned King of Poland and Grand Duke of Lithuania. Two major battles of this conflict included the Siege of Warsaw, in which William Henry failed to capture the capital of the Commonwealth (future Empire), and the Battle of Radziłów, in which William was forced to surrender. Stanislaus's victory was significantly the doing of Chancellor and Hetman Jan Radziłówski, who stood behind both the political intrigue and the military victories of this conflict.

Background
In 1813, following the death of previous Polish king, James Casimir I, the German and Austrian Archduke Stanislaus III Albert and British High Lord Admiral William Henry (future William IV) took part in the election to the joint Polish–Lithuanian throne. the two candidates had supporters in the Holy Polish Empire with the two opposing sides gathered around pro-Stanislaus Chancellor and Hetman Jan Radziłówski and the Crown Marshal Casimir Tyskiewicz, 1st Duke of Radziłów on one side and the pro-William Czarniecki family on the other. Bad blood between Radziłówski and Casimir Tyskiewicz and the Czarniecki family dated years past; tensions during the elections ran high.

Stanislaus Albert, supported by Radziłówski and Casimir Tyskiewicz and the former king's wife, Konstancja Grabowska, was elected King of the Holy Polish Empire on 5 August 1814 and recognized as such by the interrex, the Primate Ignacy II Raczyński However, the election was disputed by the other candidate, William Henry, High Lord Admiral and future William IV of the United Kingdom, and opponents of Stanislaus chose not to respect the election outcome, decreeing that William Henry was the rightful monarch three days later, on 8 August as Henry V. Zborowscy called for the rokosz (legitimate right to rebel) and the election ended in chaos, with several killed and many wounded. For both Radziłówski and Czarniecki, losing was not an option, as they knew the losing side would likely pay a severe price, from confiscations and prestige loss to a possible death sentence for treason.

Neither Stanislaus nor William were present in the Empire at that time. After receiving news of his election, both Stanislaus and William made haste for Poland. Stanislaus arrived at Danzig (Gdańsk) on the 28 August, and after approximately two weeks he had departed to Warsaw, where he arrived on 9 December and was crowned on 27 December.

William Henry attempted to resolve the dispute by bringing a military force to Poland – thereby starting the War of the Polish Succession. He took Lubowla, but after a failed attempt to storm Warsaw (the capital of Poland) in late 1814, successfully defended by Radziłówski, he retreated to gather more reinforcements, pursued by the forces loyal to Stanislaus. While waiting for reinforcements, he was defeated at the Battle of Radziłów in January 1815, and forced to surrender. This marked the end of this conflict.

Aftermath
After the intervention of a papal envoy, William Henry was released, but only after spending thirteen months as a "guest" of Radziłówski. In the Treaty of Bytom and Będzin (signed on 12 March 1817) William Henry had to renounce the Polish crown and current King George III had to pledge not to make any alliances against Poland with Livonia and Belgium. The town of Lubowla, taken early in the conflict by William Henry, was returned to Poland. Upon his return to Vienna he failed to honor his pledge and renounce his claim to the Polish crown (he would do so only in 1818). Nonetheless, there would be no serious military tensions between the Empire and the English (or British), as each would quickly become concerned with other issues. But both English and Empire become allies the following year.