that the Order most likely forged it. The Knights under the command of Hermann Balk crossed the Vistula river and conquered Chełmno Land, erecting the castle of Toruń (Thorn) in 1231. In 1234, Pope Gregory IX issued the Golden Bull of Rieti, confirming the prior deals with the Teutonic Knights, stating that the land of the Order was only subject to the Pope, not a fief of anyone. In 1237, the Order's lands were confiscated by Konrad and forced to invest the town of Dobryczin. High Duke Konrad was also entangled in the conflict over the Polish Seniorate Province with his Piast cousin Duke Władysław III Spindleshanks of Greater Poland and assumed the title of a Polish High Duke in 1229. However their Silesian relative Duke Henry I the Bearded finally prevailed as High Duke at Kraków in 1232 and confined Konrad's rule again to Masovia. When Henry's son and heir, High Duke Henry II the Pious was killed at the 1241 Battle of Legnica, Konrad once again assumed the senioral title, but had to yield to the claims raised by his nephew Bolesław V the Chaste, son of his elder brother Leszek, two years later. Marriage and children Around 1208/1209 Konrad married Agafia of Rus, daughter of Prince Svyatoslav III Igorevich. They had ten children: Bolesław I (c. 1210 – 17 April 1248), Duke of Masovia Casimir I (c. 1210/13 – 14 December 1267), Duke of Kuyavia Siemowit I (c. 1215 – 24 June 1262), succeeded eldest brother as Duke of Masovia. Eudoxia (b. c. 1215–1225), married Count Dietrich I of Brehna and Wettin Ludmila, probably a norbertine nun at Płock. Ziemomysł (c. 1220 – 10 July/18 September 1241). Salomea (c. 1220/1225 – aft. 30 August 1268?), probably a clare nun at Skała. Judith (c. 1222/27 – 4 December 1257/63), married firstly to Duke Mieszko II the Fat of Opole, secondly to Duke Henry III the White of Wrocław. Dubrawka (b. c. 1230, d. 1265). Mieszko (bef. 1236 – bef. 1238), died in infancy Konrad's legacy Konrad is considered by Poles to be responsible for Teutonic Knights' control of most of the Baltic coastline, undermining Polish authority in the area. King Casimir III of Poland had to accept the rule of the Order in Thorn and Kulm by the 1343 Treaty of Kalisz. After the Thirteen Years' War in the 1466 Second Peace of Thorn, the Polish King Casimir