Grudziądz (, ) is a city in northern Poland, with 92,552 inhabitants (2021). Located on the Vistula River, it lies within the Kuyavian-Pomeranian Voivodeship and is the fourth-largest city in its province. The Old Town of Grudziądz and 14th-century granaries were declared National Historic Monuments of Poland. Geographical location Grudziądz is located close to the east shore of the river Vistula, approximately north-east of Świecie, south of Gdańsk and south-west of Kaliningrad. It is located in Chełmno Land. History Early medieval Poland Grudziądz was founded by the Duke of Poland, Bolesław I the Brave of the Piast dynasty. Initially Grudziądz was a defensive stronghold, known as a gord. The fortress and tower were built to protect the Poles from attacks by the Baltic Prussians. Monastic State of the Teutonic Knights The settlement was re-fortified again from 1234 by the Teutonic Order. The erection of the castle, with the help of stone as building material, was begun around the middle of the 13th century. Under the protection of the castle the settlement gradually began to develop into a town. In 1277 both "the castle and the town" were besieged heavily by the Yotvingians. The settlement adopted Kulm law in 1291 while under the rule of the monastic state of the Teutonic Knights. The oldest building parts of the Catholic St. Nicholas' Church stem from the end of the 13th century. The Holy Spirit Church, which apparently was founded during the 13th century, is mentioned together with the town's hospital for the first time in 1345. Other documents reveal that in the 14th century the town already had a well-developed infrastructure. A document of 1380, as an example, refers to the construction of an aqueduct, a fountain and a town-hall cellar. During the era of the State of the Teutonic Knights, Graudenz had become a distinguished trade center in particular for textiles and agricultural products including grain. Around 1454, Graudenz had already reached about the same level of economic development as other towns in the western part of the State of the Teutonic Order, such as Danzig (Gdańsk), Elbing (Elbląg), Thorn (Toruń), Marienburg (Malbork), Kulm (Chełmno), Konitz (Chojnice), Neumark (Nowe Miasto Lubawskie) and Preußisch Stargard (Starogard Gdański). Kingdom of Poland In 1440, the city co-founded the Prussian Confederation which opposed the Monastic State of the Teutonic Knights. At the beginning of the Thirteen Years' War (1454–66), the citizens forced the Teutonic Order