Wikipedia
Warmians (also Warmi) were one of the Prussian clans. They lived in Warmia (, , , ), a territory since 1945 largely in Poland. It was situated between the Vistula Lagoon, Łyna and Pasłęka Rivers.
Soon after arrival of the first dukes of the Polans in Poland, centuries of Polish attempts at conquest of the native Prussians began in 997 AD. The preferred method was to try to convert the still heathen Prussians to Christianity, and thereby also acquire their land. A number of crusades followed, called by Konrad of Masovia, as well as attacks on Prussian land of the Yotvingians, which later became Polish Podlasie, and of the Sudovians and Galindians. To speed up and enforce this pressure on Prussians and Pomeranians, the duke Konrad, who had already called for crusade in 1209, then called in the Teutonic Order.
The Warmians, along with the other Prussians, were conquered by the Teutonic Knights, a crusading military order under direct command of the pope. The Knights conquered the Prussians and converted them to Christianity. Many cities and towns were built and the population increased by bringing in colonists from Germany and Poland, as well as other countries of Europe. The Prussians were eventually assimilated by the colonists and the Old Prussian language became extinct by the end of the 17th century or beginning of the 18th century.