Question: What is the date of death of Alexander Of Masovia's father?

Knowledge 1: Alexander of Masovia
Alexander of Masovia (pl: "Aleksander mazowiecki"; 1400 - 2 June 1444) was a Polish prince member of the House of Piast from the Masovian branch.He was Bishop of Trento since 1425, titular Patriarch of Aquileia since 1439, Cardinal nominated by Antipope Felix V as titular of the diocese of St. Lawrence at Damascus ("San Lorenzo in Damaso") since 1440, titular Bishop of Chur since 1442 and rector at St. Stephen's Cathedral, Vienna since 1442, a diplomat.He was the second son of Siemowit IV, Duke of Masovia and Alexandra of Lithuania, daughter of Algirdas. [SEP] Knowledge 2: Siemowit IV, Duke of Masovia
Siemowit IV (Ziemowit IV), also known as Siemowit IV the Younger(pl: "Siemowit IV Młodszy"; ca. 1353/1356 – 21 January 1426), was a Polish prince member of the House of Piast from the Masovian branch, from 1373/74 Duke of Rawa, and after the division of the paternal inheritance between him and his brother in 1381, ruler over Rawa, Płock, Sochaczew, Gostynin, Płońsk and Wizna, since 1386 hereditary Polish vassal, since 1388 ruler over Belz, during 1382–1401 he lost Wizna and during 1384–1399 and 1407–1411 he lost Zawkrze, during 1384–1399 he lost Płońsk, taken by the Teutonic Order.He was the second son of Siemowit III, Duke of Masovia and his first wife Euphemia, daughter of Nicholas II of Opava.Already during his father's lifetime, Siemowit IV received his own district, Rawa Mazowiecka (ca. 1373/74), and as a result of the partition of Masovia between him and his older brotherJanuszI after the death of their father on 16 June 1381, Siemowit IV finally obtain the totality of his domains:Rawa, Płock, Sochaczew, Gostynin, Płońsk and Wizna.
Knowledge 1: Alexander of Masovia
Alexander of Masovia (pl: "Aleksander mazowiecki"; 1400 - 2 June 1444) was a Polish prince member of the House of Piast from the Masovian branch.He was Bishop of Trento since 1425, titular Patriarch of Aquileia since 1439, Cardinal nominated by Antipope Felix V as titular of the diocese of St. Lawrence at Damascus ("San Lorenzo in Damaso") since 1440, titular Bishop of Chur since 1442 and rector at St. Stephen's Cathedral, Vienna since 1442, a diplomat.He was the second son of Siemowit IV, Duke of Masovia and Alexandra of Lithuania, daughter of Algirdas. [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."
Knowledge 1: Siemowit IV, Duke of Masovia
Siemowit IV (Ziemowit IV), also known as Siemowit IV the Younger(pl: "Siemowit IV Młodszy"; ca. 1353/1356 – 21 January 1426), was a Polish prince member of the House of Piast from the Masovian branch, from 1373/74 Duke of Rawa, and after the division of the paternal inheritance between him and his brother in 1381, ruler over Rawa, Płock, Sochaczew, Gostynin, Płońsk and Wizna, since 1386 hereditary Polish vassal, since 1388 ruler over Belz, during 1382–1401 he lost Wizna and during 1384–1399 and 1407–1411 he lost Zawkrze, during 1384–1399 he lost Płońsk, taken by the Teutonic Order.He was the second son of Siemowit III, Duke of Masovia and his first wife Euphemia, daughter of Nicholas II of Opava.Already during his father's lifetime, Siemowit IV received his own district, Rawa Mazowiecka (ca. 1373/74), and as a result of the partition of Masovia between him and his older brotherJanuszI after the death of their father on 16 June 1381, Siemowit IV finally obtain the totality of his domains:Rawa, Płock, Sochaczew, Gostynin, Płońsk and Wizna. [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: 21 January 1426