Question: Who is the father of Anna Of Masovia?

Knowledge 1: Anna of Masovia
Anna of Masovia (c. 1498 – after 26 January 1557 in Jaroslaw) was Princess of Mazovia and a member of the House of Piast.She was the last representative of the line of Masovian-Piast.She was the second daughter of Konrad III of Masovia and Anna Radziwiłł.She was a sister of Dukes Janusz III of Masovia and Stanislaus of Masovia, and Sophia, who married Stephen VII Báthory. [SEP] Knowledge 2: Anna Radziwiłł (nobility)
Anna Radziwiłłówna  (1475 or 1476 – 15 March 1522) was a Lithuanian noble woman and Duchess of Masovia.She was the daughter of Mikołaj Radziwiłł and his first wife, Zofia Moniwidówna.She was born in 1475 or 1476.Anna was married to Konrad III Rudy of the Masovian Piast Dynasty between 29 September 1496 and 2 April 1497.She died on the night of 14/15 March 1522.She was buried in the cloister of Bernardin's in Warsaw.She is one of the characters on the famous painting by Jan Matejko, "Prussian Homage".
Knowledge 1: Anna of Masovia
Anna of Masovia (c. 1498 – after 26 January 1557 in Jaroslaw) was Princess of Mazovia and a member of the House of Piast.She was the last representative of the line of Masovian-Piast.She was the second daughter of Konrad III of Masovia and Anna Radziwiłł.She was a sister of Dukes Janusz III of Masovia and Stanislaus of Masovia, and Sophia, who married Stephen VII Báthory. [SEP] Knowledge 2: Sophia of Masovia
Sophia of Masovia( 1497/1498- before 11 March 1543) was a Princess of Masovia, daughter of Konrad III Rudy, Duke of Masovia and his wife Anna Radziwiłł.She was a member of the House of Piast.On 17 September 1520 in Warsaw, Sophia was married by proxy to Stephen VII Báthory.On 17 January 1521, Sophia and her entourage went to Hungary, where in February there was a formal marriage.The couple had three children:Anna, Stephen and Klara; however, other sources claim that Klara was the couple's only child.Klara was engaged to Carl, Duke of Münsterberg, but died in 1535, before the marriage took place.After the death of Stephen in 1530, Sophia was married to Croatian magnate Louis Pekry.Sophia's second marriage was childless.She then died sometime before 11 March 1543.Sophia had three siblings: Stanislaus I of Masovia, Janusz III of Masovia and Anna of Masovia, both her brothers died childless and so Anna and Sophia were the last Masovian Piasts.Soon after Janusz's death, the Duchy of Masovia was annexed into the kingdom of Poland, despite resistance from some of the Masovian nobility.They tried to retain their independence and argued that the Duchy should be inherited by the female relatives( such as Anna or Sophia).The Polish king refused to recognize their demands.Anna was made titular Duchess of Masovia.
Knowledge 1: Anna Radziwiłł (nobility)
Anna Radziwiłłówna  (1475 or 1476 – 15 March 1522) was a Lithuanian noble woman and Duchess of Masovia.She was the daughter of Mikołaj Radziwiłł and his first wife, Zofia Moniwidówna.She was born in 1475 or 1476.Anna was married to Konrad III Rudy of the Masovian Piast Dynasty between 29 September 1496 and 2 April 1497.She died on the night of 14/15 March 1522.She was buried in the cloister of Bernardin's in Warsaw.She is one of the characters on the famous painting by Jan Matejko, "Prussian Homage". [SEP] Knowledge 2: Sophia of Masovia
Sophia of Masovia( 1497/1498- before 11 March 1543) was a Princess of Masovia, daughter of Konrad III Rudy, Duke of Masovia and his wife Anna Radziwiłł.She was a member of the House of Piast.On 17 September 1520 in Warsaw, Sophia was married by proxy to Stephen VII Báthory.On 17 January 1521, Sophia and her entourage went to Hungary, where in February there was a formal marriage.The couple had three children:Anna, Stephen and Klara; however, other sources claim that Klara was the couple's only child.Klara was engaged to Carl, Duke of Münsterberg, but died in 1535, before the marriage took place.After the death of Stephen in 1530, Sophia was married to Croatian magnate Louis Pekry.Sophia's second marriage was childless.She then died sometime before 11 March 1543.Sophia had three siblings: Stanislaus I of Masovia, Janusz III of Masovia and Anna of Masovia, both her brothers died childless and so Anna and Sophia were the last Masovian Piasts.Soon after Janusz's death, the Duchy of Masovia was annexed into the kingdom of Poland, despite resistance from some of the Masovian nobility.They tried to retain their independence and argued that the Duchy should be inherited by the female relatives( such as Anna or Sophia).The Polish king refused to recognize their demands.Anna was made titular Duchess of Masovia.

Answer: Konrad III Rudy