Question: What is the date of death of Doamna Chiajna's husband?

Context paragraphs:
title: Mircea the Shepherd
paragraph_text: Mircea the Shepherd, in Romanian Mircea Ciobanul (died 25 September 1559), was the Voivode (or Prince) of Wallachia three times: January 1545 (he entered Bucharest on 17 March)–16 November 1552; May 1553–28 February 1554 (leaving Bucharest that March); and January 1558–21 September 1559.
title: Bill Smith (footballer, born 1897)
paragraph_text: William Thomas Smith( born 9 April 1897, date of death unknown) was an English professional footballer.
title: Thomas Scott (diver)
paragraph_text: Thomas Scott( 1907- date of death unknown) was an English diver.
title: Harry Wainwright (footballer)
paragraph_text: Harry Wainwright( born 1899; date of death unknown) was an English footballer.
title: Harry Johnson (wrestler)
paragraph_text: Harry Johnson( 1903- date of death unknown) was an English wrestler.
title: Etan Boritzer
paragraph_text: 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 include What 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."
title: Doamna Chiajna
paragraph_text: Doamna Chiajna (1525–1588) was a Princess consort of Wallachia. She was married to Mircea the Shepherd. She was regent in Wallachia in 1559–1575. She was born as Ana in Poland as the daughter of prince Peter IV Rareș, and married prince Mircea the Shepherd in 1545. She founded the first school in Romania: Câmpulung in 1552. After the death of her spouse in 1559, she became regent in Wallachia on behalf of her son Petru cel Tânăr. She is described as an energetic, intelligent and gifted politician. In 1575, she was abducted by the Ottomans and deported to Aleppo in Syria. Last sourced report on 1588 and her resting place whereabouts remained unclear.
title: Albert Thompson (footballer, born 1912)
paragraph_text: Albert Thompson( born 1912, date of death unknown) was a Welsh footballer.
title: Fred Bradley (rower)
paragraph_text: Frederick Bradley( 1908- date of death unknown) was an English rower.
title: Theodred II (Bishop of Elmham)
paragraph_text: 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.

Reasoning steps:
Doamna Chiajna spouse Mircea the Shepherd
Mircea the Shepherd date of death 21 September 1559

Answer: spans: 21 September 1559