Question: Anna of Cilli and her daughter Hedwig Jagiellon were 15th-century figures in which European country's royal family?

Context paragraphs:
Jubilee (musical): Jubilee is a musical comedy with a book by Moss Hart and music and lyrics by Cole Porter.  It premiered on Broadway in 1935 to rapturous reviews.  Inspired by the recent silver jubilee of King George V of Great Britain, the story is of the royal family of a fictional European country.  Several of its songs, especially "Begin the Beguine" and "Just One of Those Things", became independently popular and have become part of the American Songbook.

Count Vertigo: Count Vertigo is a fictional character created by Gerry Conway, Trevor Von Eeden and Vince Colletta as an enemy of Black Canary and later Green Arrow in the DC Comics Universe.  Count Vertigo is the last descendant of the royal family that ruled the small eastern European country of Vlatava that was taken over by the Soviets and later became devastated by the Spectre.

Windsor Castle: Windsor Castle is a royal residence at Windsor in the English county of Berkshire.  It is notable for its long association with the English and later British royal family and for its architecture.  The original castle was built in the 11th century after the Norman invasion of England by William the Conqueror.  Since the time of Henry I, it has been used by the reigning monarch and is the longest-occupied palace in Europe.  The castle's lavish early 19th-century State Apartments were described by the art historian Hugh Roberts as "a superb and unrivalled sequence of rooms widely regarded as the finest and most complete expression of later Georgian taste".  Inside the castle walls is the 15th-century St George's Chapel, considered by the historian John Martin Robinson to be "one of the supreme achievements of English Perpendicular Gothic" design.

Anna of Cilli: Anna of Cilli or Anne of Celje (  1381 – 21 May 1416) was Queen consort of Poland (1402–1416).  She was the second wife of Jogaila (Władysław II Jagiełło), King of Poland and Supreme Duke of Lithuania (reigned 1387–1434).  Their marriage was politically motivated to strengthen Jogaila's ties with the Piast dynasty and his claims to the Polish throne.  Their marriage was rather distant and during fourteen years Anna bore only one daughter, Hedwig Jagiellon, who died without issue.

Hedwig Jagiellon, Electress of Brandenburg: Hedwig Jagiellon (Lithuanian: "Jadvyga Jogailaitė" , Polish: "Jadwiga Jagiellonka" , German: "Hedwig Jagiellonica" ; 15 March 1513 – 7 February 1573) was a member of the Polish Jagiellon dynasty and an Electress of Brandenburg.

Liudvikas Jakavičius: Liudvikas Jakavičius (22 June 1871 – 20 August 1941) was a writer, journalist, publisher, theatre director, banker and nobleman.  He was born in Akmenė (Lithuania) and died in Anykščiai (Lithuania).  He was married to Honorata Grimalauskaitė-Jakavičienė, a Lithuanian – Polish noblewoman and public figure.  Honorata's father, Juozas Grimalauskas, was a wealthy Lithuanian – Polish Duke and Count close to the Drucki – Lubecki Dynasty, Royal Family of the old Princedom of Druckiai (Belarus), political family of the Lithuanian Royal Family (House of Gediminas), political family of the Polish-Lithuanian Royal Family (House of Jagiellon) and founders of the National Bank of Poland.  Liudvikas and Honorata had five children (Gražina; Liudas; Donatas Bronislovas, Juozas and Artūras) all of which were artists devoted to music and theatre.  His eldest son was Liudas Jakavičius-Grimalauskas, President of the Siauliai Drama Theatre, composer of the first Lithuanian tango (Sutemos tango) and a famous pianist, disciple of the world-famous Russian musician Dmitry Kabalevsky.  His only daughter was the actress Gražina Jakavičiūtė-Grimalauskaitė Šaltenienė, remembered by her performances at the Lithuanian National Drama Theatre.  His son Donatas Bronislovas Jakavičius – Grimalauskas was a brilliant violinist who delighted with his Stradivarius in the best orchestras in the world, including Lithuanian National Opera and Ballet Orchestra, Kaunas Philharmonic Orchestra, Royal Concertgebouw Orchestra (considered as the best symphony orchestra in the world), Berlin Philharmonic Orchestra, Berlin Radio Symphony Orchestra, Vienna State Opera Orchestra, Belgrade Philharmonic Orchestra and Venezuela National Symphony Orchestra.

Hedwig Jagiellon, Duchess of Bavaria: Hedwig Jagiellon (Polish: "Jadwiga Jagiellonka" , Lithuanian: "Jadvyga Jogailaitė" , German: "Hedwig Jagiellonica" ) (21 September 1457 – 18 February 1502), baptized as ""Hedwigis"", was a Polish princess member of the Jagiellonian dynasty and by marriage Duchess of Bavaria.

Anna Inglese: Anna Inglese ("floruit" 1468 – 1499) was a prominent singer at the courts of Galeazzo Maria Sforza, Duke of Milan and Ferdinand I of Naples and one of the very few professional women singers working in 15th-century Italy.  Over two centuries later, she was listed in "Istoria delle donne scientiate" (History of Learned Women) simply as "excellent in music, she lived in 1470."  Little is known about her life, and what is available has come from 15th-century archival material.  She is thought to have originally come from England and hence was referred to as "Inglese" (Italian for "English").  She was also referred to as "Madamma (or Madama) Anna".  Her actual surname is unknown.

Anna Jagiellon: Anna Jagiellon (Polish: "Anna Jagiellonka" , Lithuanian: "Ona Jogailaitė" ; 18 October 1523 – 12 November 1596) was Queen of Poland and Grand Duchess of Lithuania in her own right from 1575 to 1586.  She was a daughter of Polish King Sigismund I the Old and his Italian wife Bona Sforza.  Despite multiple proposals, she remained unmarried until the age of 52.  After the death of King Sigismund II Augustus, her brother and the last male member of the Jagiellon dynasty, Anna's hand was sought by pretenders to the Polish–Lithuanian throne to maintain the dynastic tradition.  She was elected, along with her then-fiancé Stephen Báthory, as co-ruler in the 1576 royal election of the Polish–Lithuanian Commonwealth.  Their marriage was a formal arrangement and distant.  Báthory was preoccupied with the Livonian War, while Anna spent her time in Warsaw on local administrative matters and several construction works.  After Báthory's death in December 1586, she had an opportunity to claim the throne for herself (she was co-ruler and not merely a consort), but did not even attempt it.  Instead, she promoted her nephew Sigismund III Vasa, establishing House of Vasa on the Polish–Lithuanian throne for the next eighty years (1587–1668).

Hedwig Jagiellon (1408–1431): Hedwig Jagiellon (Lithuanian: "Jadvyga Jogailaitė" , Polish: "Jadwiga Jagiellonka" ; 8 April 1408, Kraków – 8 December 1431, Kraków) was a Polish and Lithuanian princess, and a member of the Jagiellon dynasty.  For most of her life she, as the only child of Wladyslaw Jagiello, was considered to be heiress of the Polish and Lithuanian thrones.  After the birth of Jagiello's sons in 1424 and 1427, Hedwig had some support for her claims to the throne.  She died in 1431 amidst rumors that she was poisoned by her stepmother Sophia of Halshany.

Supporting paragraphs: Anna of Cilli Hedwig Jagiellon (1408–1431)
Answer: Poland