Title: Frederick Jagiellon
Content:  Frederick Jagiellon (Fryderyk Jagiellończyk; 27 April 1468 – 14 March 1503) was a Polish prince, Archbishop of Gniezno, Bishop of Kraków, and Primate of Poland. He was the sixth son and ninth child of Casimir IV Jagiellon, King of Poland and Grand Duke of Lithuania, and his wife Elizabeth of Austria, known as 'Matka Jagiellonów' (Mother of the Jagiellons). Frederick ruled two dioceses with devotion. He cared about the cult of saints, the appropriate education of the clergy, took care of the liturgical life, carried out the diocesan and provincial synods. He also cared about the liturgy, foundations, and restoring of churches, including the restoration of the Kraków and Gniezno Cathedrals.
Title: Frederick Jagiellon
Content:  Frederick was born in Kraków, and was named after the Holy Roman Emperor Frederick III. His godfather was Protazy, Bishop of Olomouc. After the death of Bishop Jan Rzeszów, he was elected Archbishop of Kraków on 13 April 1488. His father sought to secure him the Bishopric of Warmia in Prussia, but the Frauenburg (now Frombork) cathedral chapter of the Diocese of Warmia elected Lucas Watzenrode in 1489. He worked for the Polish throne in 1492 together with his brother, John I Albert, and in 1501 he contributed to the nomination of another of his brothers, King Alexander, who strengthened the Polish–Lithuanian union. After the death of Zbigniew Oleśnicki on 2 October 1493, he was appointed Archbishop of Gniezno (and Polish Primate at the same time). From that moment on he held the two traditionally most important bishoprics in Poland. His position in the Polish Church strengthened after his promotion to cardinal by Pope Alexander VI on 20 September 1493, having received the title of Sanctae Lucia in Septomsoliis in December that year. After being appointed Archbishop of Gniezno, Frederick received episcopal consecration. He died in the Bishop's Palace in Kraków after a long illness, in March 1503.
Title: Hedwig Jagiellon (1408–1431)
Content:  son of Frederick I, Elector of Brandenburg, who sought Polish alliance in the long-standing Brandenburg–Pomeranian conflict. According to the terms of the agreement, the marriage would take place when Frederick II reached age 14 in 1427. Five years after the marriage, Frederick II would be eligible to become King of Poland and Grand Duke of Lithuania. The young Brandenburg prince had to live in Poland as soon as was possible, in order to get acquainted with the language and customs of his future country. The agreement would be void if Jagiello had surviving sons. Ten months later, Jagiello married Sophia of Halshany, who was just a few years older than Hedwig. 
Title: Alexander Jagiellon
Content:  Alexander Jagiellon (Aleksander Jagiellończyk; Aleksandras Jogailaitis; 5 August 1461 – 19 August 1506) of the House of Jagiellon was the grand duke of Lithuania and later also king of Poland. He was the fourth son of Casimir IV Jagiellon. He was elected grand duke of Lithuania on the death of his father (1492) and king of Poland on the death of his brother John I Albert (1501).
Title: Family of Jogaila
Content:  This page describes relatives of Jogaila, who was Grand Duke of Lithuania, and, known under the name Wladyslaw II Jagiello, king of Poland. Family relations up to two generations before him, and three generations after him are mentioned.
Title: Hedwig Jagiellon (1408–1431)
Content:  I was not satisfied with the marriage and sent his son to Kraków to be with his fiancé. Tensions continued to rise as Brandenburg did not provide troops in the Gollub War against the Teutonic Knights. Sigismund, Holy Roman Emperor, lobbied against the marriage while Scandinavian King Eric renewed his proposal for the Polish–Scandinavian–Pomeranian alliance against Brandenburg. Despite political pressure, Jagiello did not annul the agreement. Fearing an assassination attempt, Grand Duke Vytautas took Frederick II from Kraków to Lithuania in 1424. In October 1424, Sophia gave birth to Jagiello's son. Frederick I continued to pursue the marriage. A party of Polish nobles wanted Hedwig and her future husband to succeed 
Title: Jagiellonian dynasty
Content:  The Jagiellonian dynasty, or simply Jagiellon, was a royal dynasty, founded by Jogaila, the Grand Duke of Lithuania, who in 1386 was baptized as Władysław, married Queen Hedwig of Poland, and was crowned King of Poland as Władysław II Jagiełło. The dynasty reigned in several Central European countries between the 14th and 16th centuries. Members of the dynasty were Kings of Poland (1386–1572), Grand Dukes of Lithuania (1377–1392 and 1440–1572), Kings of Hungary (1440–1444 and 1490–1526), and Kings of Bohemia and imperial electors (1471–1526). The dynasty was a cadet branch of Gediminids. The personal union between the Kingdom of Poland and the Grand Duchy of Lithuania (converted in 1569 with the Treaty of Lublin into the Polish–Lithuanian Commonwealth) is the reason for the common appellation "Poland–Lithuania" 
Title: Jagiellonian dynasty
Content:  The rule of Piasts, the earlier Polish ruling house (c. 962–1370) had ended with the death of King Casimir III the Great. Gediminids, the immediate predecessors of the first Jagiellonian, were rulers of medieval Lithuania with the title of Grand Duke. Their realm, the Grand Duchy of Lithuania, was chiefly inhabited by Lithuanians and Ruthenians. Jogaila, the eponymous first ruler of the Jagiellonian dynasty, started as the Grand Duke of Lithuania. As a result of the Union of Krewo he then converted to Christianity and married the 11-year-old Hedwig of Poland (Jadwiga in Polish) (daughter of King Louis I of Hungary from the Angevins Dynasty). Thereby he became King of Poland and founded the dynasty. Angevin rulers were the second and Jagiellonian third dynasty of Polish Kings.
Title: Hedwig Jagiellon (1408–1431)
Content:  Hedwig Jagiellon (Jadvyga Jogailaitė, 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.
Title: Jagiellonian dynasty
Content:  The name comes from Jogaila (Jagiełło), the first Grand Duke of Lithuania to become King of Poland. In Polish, the dynasty is known as Jagiellonowie and the patronymic form: Jagiellończyk; in Lithuanian it is called Jogailaičiai, in Belarusian Яґайлавічы (Jagajłavičy), in Hungarian Jagelló, and in Czech Jagellonci, as well as Jagello or Jagellon in Latin. Jogaila name etymologically means strong rider, from Lithuanian words joti (to ride) and gailus (strong, powerful).

Question: Who is the father of Frederick Jagiellon?
Answer: Casimir IV Jagiellon.