Question: What is the date of death of Yolanda Of Vianden's mother?

Knowledge 1: Yolanda of Vianden
Mother Yolanda (or Yolande, Iolanda) of Vianden, O.P., (1231–1283) was the youngest daughter of Count Henry I of Vianden and Margaret, Marchioness of Namur.She joined the Dominican monastery in Marienthal, Luxembourg, against the wishes of her parents when she was very young.She later became its devout prioress and is now a legend in the history of that nation. [SEP] Knowledge 2: Margaret, Marchioness of Namur
Margaret, Marchioness of Namur (c. 1194 – 17 July 1270) was ruling Marchioness of Namur in 1229-1237.She was the daughter of Peter II of Courtenay and Yolanda of Flanders.
Knowledge 1: Yolanda of Vianden
Mother Yolanda (or Yolande, Iolanda) of Vianden, O.P., (1231–1283) was the youngest daughter of Count Henry I of Vianden and Margaret, Marchioness of Namur.She joined the Dominican monastery in Marienthal, Luxembourg, against the wishes of her parents when she was very young.She later became its devout prioress and is now a legend in the history of that nation. [SEP] Knowledge 2: Marie de Namur
Marie of Namur, also known as Marie de Namur or Maria van Dampierre.Her titles were" Gräfin von Vianden", from her first marriage and" Dame de Pierrepont", from her second marriage to, Theobald of Bar.Born in 1322 to John I of Namur and his wife Marie of Artois.She had three sisters, including Blanche of Namur, Queen consort of Sweden and Norway, and seven brothers.In 1335/ 36, she married her first husband, Henry II, Graf of Vianden, son of Philip II, Graf of Vianden and his first wife Lucia von der Neuerburg.Henry was murdered at Famagusta in September 1337.In c. 1337, she gave birth to Maria of Vianden her first daughter from her marriage to Henry II, Graf of Vianden.Her second marriage in 1340( dispensation 9 September 1342) was to her father's second cousin, Theobald of Bar, Seigneur de Pierrepont, son of Erard of Bar, Seigneur de Pierrepont et d'Ancerville( himself son of Theobald II of Bar), and his wife Isabelle of Lorraine( daughter of Theobald II, Duke of Lorraine).This marriage produced two daughters, Yolande de Bar( b. c 1343 – d. c 1410) and Elisabeth de Bar( b. c 1345 – d. before 11 May 1411).Marie died somewhere before 29 October 1353/ 57.
Knowledge 1: Yolanda of Vianden
Mother Yolanda (or Yolande, Iolanda) of Vianden, O.P., (1231–1283) was the youngest daughter of Count Henry I of Vianden and Margaret, Marchioness of Namur.She joined the Dominican monastery in Marienthal, Luxembourg, against the wishes of her parents when she was very young.She later became its devout prioress and is now a legend in the history of that nation. [SEP] Knowledge 2: Etan Boritzer
Etan Boritzer( born 1950) is an American writer of children ’s literature who is best known for his book" What is God?" first published in 1989.His best selling" What is?" illustrated children's book series on character education and difficult subjects for children is a popular teaching guide for parents, teachers and child- life professionals.Boritzer gained national critical acclaim after" What is God?" was published in 1989 although the book has caused controversy from religious fundamentalists for its universalist views.The other current books in the" What is?" series includeWhat is Love?,What is Death?,What is Beautiful?,What is Funny?,What is Right?,What is Peace?,What is Money?,What is Dreaming?,What is a Friend?,What is True?,What is a Family?,What is a Feeling?"The series is now also translated into 15 languages.Boritzer was first published in 1963 at the age of 13 when he wrote an essay in his English class at Wade Junior High School in the Bronx, New York on the assassination of John F. Kennedy.His essay was included in a special anthology by New York City public school children compiled and published by the New York City Department of Education.Boritzer now lives in Venice, California and maintains his publishing office there also.He has helped numerous other authors to get published through" How to Get Your Book Published!" programs.Boritzer is also a yoga teacher who teaches regular classes locally and guest- teaches nationally.He is also recognized nationally as an erudite speaker on" The Teachings of the Buddha."

Answer: 17 July 1270