question: What is the date of death of Casimir I Of Kuyavia's father?
context: [["Boles\u0142aw of Kuyavia", ["Boles\u0142aw of Kuyavia( also known as Mieszkowic)( 1159 \u2013 13 September 1195) was a Duke of Kuyavia from 1186 until his death.", "He was the eldest child( but third- born son) of Mieszko III the Old, Duke of Greater Poland and High Duke of Poland in 1173, by his second wife Eudoxia, daughter of Grand Prince Iziaslav II of Kiev."]], ["Casimir I of Kuyavia", ["Casimir I of Kuyavia  (c. 1211 \u2013 14 December 1267), was a Polish prince member of the House of Piast, Duke of Kujawy since 1233, ruler over L\u0105d during 1239-1261, ruler over Wyszogr\u00f3d since 1242, Duke of Sieradz during 1247-1261, Duke of \u0141\u0119czyca since 1247 and Duke of Dobrzy\u0144 since 1248.", "He was the second son of Konrad I of Masovia and his wife Agafia of Rus.", "He was probably named after his grandfather, Casimir II the Just."]], ["Konrad I of Masovia", ["Konrad I of Masovia  (ca. 1187/88 \u2013 31 August 1247), from the Polish Piast dynasty, was the sixth Duke of Masovia and Kujawy from 1194 until his death as well as High Duke of Poland from 1229 to 1232 and again from 1241 to 1243."]], ["Ziemomys\u0142 of Kuyavia", ["Ziemomys\u0142 of Inowroc\u0142aw( c. 1245 \u2013 October/ 24 December 1287), was a Polish prince member of the House of Piast, Duke of Inowroc\u0142aw during 1267- 1271 and 1278- 1287, and ruler over Bydgoszcz during 1267- 1269 and 1278- 1287.", "He was the second son of Casimir I of Kuyavia and his second wife Constance, daughter of Henry II the Pious."]], ["Casimir II of \u0141\u0119czyca", ["Casimir II of \u0141\u0119czyca( pl:\" Kazimierz II \u0142\u0119czycki\"; c. 1261/62 \u2013 10 June 1294), was a Polish prince member of the House of Piast, Duke of Brze\u015b\u0107 Kujawski during 1267 \u2013 1288, Duke of Dobrzy \u0144 during 1275 \u2013 1288 and Duke of \u0141\u0119czyca since 1288 until his death.", "He was the fourth son of Casimir I of Kuyavia, but the second born from his third marriage with Euphrosyne, daughter of Casimir I of Opole.", "He was probably named after both his father and maternal grandfather."]], ["Siemowit of Dobrzy\u0144", ["Siemowit of Dobrzy \u0144( pl:\" Siemowit dobrzy\u0144ski\"; c. 1262/67 \u2013 1312), was a Polish prince member of the House of Piast, Duke of Brze\u015b\u0107 Kujawski during 1267 \u2013 1288, Duke of Dobrzy \u0144 during 1288 \u2013 1293, 1295\u2013 1303 and 1305 \u2013 1312, during 1293 \u2013 1295 in captivity in Lithuania, during 1303 \u2013 1305 deposed, since 1306 hereditary vassal of the Kingdom of Poland.", "He was the fifth son of Casimir I of Kuyavia, but the third born from his third marriage with Euphrosyne, daughter of Casimir I of Opole."]], ["Adelaide of Poland", ["Adelaide of Poland( c. late 1170s/ early 1180s \u2013 8 December 1211), was a Polish princess and member of the Piast dynasty.", "She was the daughter of Casimir II the Just, Duke of Sandomierz and High Duke of Poland, by his wife Helena of Znojmo, a P\u0159emyslid princess.", "On basis of the inscription of her tombstone at the Dominican Church and Convent of St. James in Sandomierz and two different reports of Jan D\u0142ugosz, modern historians agreed with the origin and facts from Adelaide's life.", "Today existed a dominant view in historiography consistent with her filiation and death date.", "According to them, Adelaide was indeed the daughter of Casimir II the Just and died in 1211, but was n't the foundress of the Convent of St. James and only another nun there.", "In the 19th century, appeared a theory which states that Adelaide was the daughter of Casimir I of Kuyavia, who entered in the Convent of St. James as a nun and died there in 1291.", "This view, accepted by several scholars, has been disputed.", "More recent historiography recognized her as the daughter of Casimir II the Just, founder of the Convent, in which was she buried after her death in 1211."]], ["Constance of Wroc\u0142aw", ["Constance of Wroc\u0142aw( c.1221\u201327 \u2013 21 or 23 February 1257) was a Princess of Silesia and the Duchess of Kuyavia.", "She was a member of the Polish House of Piast and mother of Leszek the Black and Ziemomys\u0142 of Kuyavia."]], ["Theodred II (Bishop of Elmham)", ["Theodred II was a medieval Bishop of Elmham.", "The date of Theodred's consecration unknown, but the date of his death was sometime between 995 and 997."]], ["Euphemia of Kuyavia", ["Euphemia of Kuyavia( c. 1265 \u2013 March 18, 1308) was a Kuyavian princess, who was Queen consort of Galicia- Volhynia.", "She was the daughter of Casimir I of Kuyavia by his third wife Euphrosyne, daughter of Casimir I of Opole.", "Euphemia was sister of W\u0142adys\u0142aw I the Elbow- high, she was wife of Yuri I of Galicia and mother of Andrew of Galicia and Lev II of Galicia.", "The only preserved evidence of Euphemia's existence is from Jan D\u0142ugosz's Yearbooks, which reported that on March 18, 1308 Euphemia died and that she was the daughter of Prince Casimir and the wife of Yuri I, who died in the same year on April 21, which was also his birthday."]]]
supporting_facts: [["Casimir I of Kuyavia", 1], ["Konrad I of Masovia", 0]]
evidences: [["Casimir I of Kuyavia", "father", "Konrad I of Masovia"], ["Konrad I of Masovia", "date of death", "31 August 1247"]]
answer: 31 August 1247