The Prussian Confederation (, ) was an organization formed on 21 February 1440 at Kwidzyn (then officially Marienwerder) by a group of 53 nobles and clergy and 19 cities in Prussia, to oppose the arbitrariness of the Teutonic Knights. It was based on an earlier similar organization, the Lizard Union established in 1397 by the nobles of Chełmno Land. In 1454, the leader of the Confederation, Johannes von Baysen (Jan Bażyński), formally asked King Casimir IV Jagiellon, to incorporate Prussia into the Kingdom of Poland. This marked the beginning of the Thirteen Years' War between the Order's State and Poland, with the cities co-financing the military costs of the latter. Background According to the 1411 First Peace of Thorn which followed the Teutonic Knights' defeat in the Battle of Grunwald, the Teutonic Order had to pay high reparations to the Kingdom of Poland. The monastic state imposed high taxes on the cities to raise the funds as well as to re-arm for another war against Poland. In the 1420s, Grand Master Paul von Rusdorf brought stability to the Order and its relations, but fighting with Poland resumed in 1431, when the Knights' invasion into Poland during the Lithuanian Civil War sparked another Polish-Teutonic conflict. Establishment After about three decades of growing discontent, the burghers, nobility and landowners from the Teutonic state (see Prussian estates) organized themselves to oppose the rule of the order more effectively. The decision to establish the organization was made at a convention held in Elbląg on February 21, 1440. The convention was attended by representatives of the cities of Chełmno (Culm), Elbląg (Elbing), Toruń (Thorn), Gdańsk (Danzig), Braniewo (Braunsberg), Królewiec (Königsberg), and Knipawa (Kneiphof) as well as nobles from various areas. On 14 March 1440, a group of 53 nobles and clergy and 19 cities, under the leadership of the Hanseatic cities of Danzig (Gdańsk), Elbing (Elbląg), Thorn (Toruń) and Königsberg (Królewiec), founded the Prussian Confederation in Marienwerder (Kwidzyn). More towns joined later on (see Participating towns below). In Danzig, the new members signed a document which was kept in the archives of Thorn. The official representatives of the Confederation were the city councils of Chełmno and Toruń, and the knights of Chełmno Land. After Grand Master Paul von Rusdorf died in 1441, his successor, Konrad von Erlichshausen, continued to negotiate a compromise until his own death in 1449. The confederation lobbied for support against the