Chełmża (, earlier Culmsee), is a town in north-central Poland, in the Toruń County, Kuyavian-Pomeranian Voivodeship. It is located at around . It is one of the historic centers of Chełmno Land. Geography The town Chełmża is placed at the lake named Jezioro Chełmżyńskie (area 2.71 km²), earlier the lake itself was named Culmsee and therefore eponym of the town, that earlier had the name Culmsee, too (see History). Demographics Number of inhabitants by year History The first signs of settlement date to 10,000 BC when reindeer hunters made their visits to the area. Around 4500 BC the first agricultural settlements were founded. Goth tribes also moved through the area on their trek from Scandinavia and North Germany. Visible signs of existence of the Old Prussians also exist. Around the 7th century the Slavic Lechitic tribe of Goplans arrived in the area. In the time of first Piasts and the formation of Poland, Chełmno Land and the settlement of Łoza (now the town of Chełmża) was incorporated into Chełmno castellany. After the death of Bolesław III Wrymouth in 1138 it was handed over to his son Bolesław IV the Curly – as part of Masovia within Piast-ruled Poland. The fights with nearby Old Prussian tribes resulted in several raids that destroyed the area. In the 13th century the ruler of the area was Konrad I who in order to Christianize the Old Prussians brought a missionary Bishop Christian of Oliva. The bishop was granted a number of possession including the settlement of Łoza. Later Teutonic Knights were granted local lands to support the bishop by military means. However, in time the knights took over the possession of Christian's diocese, dividing the area into four dioceses in 1243, including the Roman Catholic Diocese of Chełmno. At the end of 1245 Heidenreich of the Diocese of Chełmno (Culm) became the bishop of diocese. He picked Łoza as place of his stay. It was during that time that Łoza received its new name Culmense and became part of the residence of the bishop who resided and governed in Warmia from 1245 to 1263. In 1251 (before July 22) Bishop Heidenreich bestowed city rights to Łoza and renamed it Culmsee (Kulmsee). On July 22, the bishop also founded the cathedral which was built starting in 1254. Bishop Heidenreich received permissions for his undertakings directly from the pope. Later, in 1255 the four dioceses of