Title: Peter I of Portugal
Content:  Peter I (Portuguese: Pedro I, ; 8 April 1320 – 18 January 1367), called the Just (o Justo) or the Cruel (o Cruel), was King of Portugal from 1357 until his death. He was the third but only surviving son of Afonso IV of Portugal and his wife, Beatrice of Castile.
Title: Peter I, Count of Urgell
Content:  Peter I (Pedro, ) (23 February 1187 - 2 June 1258) was the second son of King Sancho I of Portugal and his wife Dulce, infanta of Aragon, and would eventually become Count of Urgell and Lord of the Balearic Islands.
Title: Peter I of Portugal
Content:  In 1328, Peter's father, Afonso IV arranged for the marriage of his eldest daughter, Maria, to Alfonso XI of Castile. In 1334, she bore him a son, who ultimately became Peter of Castile. However, Maria returned home to her father in Portugal in 1335 because her royal husband soon after their marriage had begun a long affair with the beautiful and newly widowed Leonor de Guzman, which the Castilian king refused to end. Alfonso's cousin, Juan Manuel, Prince of Villena, had been rebuffed by the Castilian king in 1327 when the two-year child marriage between his daughter Constanza (granddaughter of James II of Aragon) and Alfonso had 
Title: Peter, Constable of Portugal
Content:  His father's position as the regent of the Kingdom of Portugal gained him special advantages. In 1443, after the death of his cousin Infante Diogo and by the instigation of his father, Peter was elected the Constable of Portugal, making him one of the most powerful military men in the kingdom. Afonso, Marquis of Valença, the son of his half-uncle Afonso, 1st Duke of Braganza, had expected to become constable, but Peter's father had appoint him instead. This political move along with Afonso V's marriage to Isabella of Coimbra, Peter's sister, instead of the daughter of the Duke of Braganza destroyed the relationship of these former allies. In 1448, when 
Title: Peter II of Portugal
Content:  Third son of King John IV and Queen Luisa, he was created Duke of Beja and Lord of the House of the Infantado. Following his father's death, his mother became regent for the new king Afonso VI, Peter's elder, partially paralysed, and mentally unstable brother. In 1662 Afonso put away his mother and assumed control of the state. In January 1668, shortly before Spanish recognition of Portugal's restoration of independence, Peter acquired political ascendancy over his brother and was appointed regent, banishing Afonso to the Azores and, later, Sintra where he died in 1683. Peter thereupon inherited the throne. Peter not only inherited his brother's throne but also wed his former spouse, Queen Marie-Françoise of Savoy (1646–1683). They had one daughter, Isabel Luísa, Princess of Beira (1669–90), who was heir presumptive.
Title: Peter II of Portugal
Content:  Dom Pedro II (Peter II; 26 April 1648 – 9 December 1706), nicknamed "the Pacific", was the King of Portugal from 1683 until his death, previously serving as regent for his brother Afonso VI from 1668 until his own accession. He was the fifth and last child of John IV and Luisa de Guzmán.
Title: Peter I of Portugal
Content:  where she was detained, and they decapitated her in front of one of her young children. Enraged, Peter revolted against his father. Afonso defeated his son within a year, but died shortly thereafter, and Peter succeeded to the throne in 1357. The love affair and father-son conflict inspired more than twenty operas and many writers, including: the Portuguese national epic Os Lusíadas by Luís de Camões, the Spanish "Nise lastimosa" and "Nise laureada" (1577) by Jerónimo Bermúdez and 'Reinar despues de morir' by Luís Vélez de Guevara, as well as "Inez de Castro" by Mary Russell Mitford and Henry de Montherlant's French drama La Reine morte.
Title: Peter I of Portugal
Content:  in secret. According to the chronicle of Fernão Lopes, during this period, Peter began giving Inês's brothers, exiles from the Castilian court, important positions in Portugal and they became the heir-apparent's closest advisors. This alarmed Afonso. He worried that upon his death, civil war could tear the country apart, or the Portuguese throne would fall into Castilian hands, either as Juan Manuel fought to avenge his daughter's honor, or the de Castro brothers supported their sister. Peter claimed that he had married Inês against his father's orders. In any event, in 1355, Afonso sent three men to find Inês at the Monastery of Santa Clara-a-Velha in 
Title: Peter, Constable of Portugal
Content:  His parents were Infante Peter, Duke of Coimbra, and Isabella of Urgell. He inherited a claim to the Aragonese throne through his maternal grandfather James II, Count of Urgell, who was the last male descendant of the House of Barcelona and heir to the Crown of Aragon by the rights of agnatic primogeniture.
Title: Peter I of Portugal
Content:  in rich robes and jewels, and required all of his vassals to kiss the hand of the deceased "queen". However, contemporary evidence that the event occurred is minimal; Peter did have Inês' body removed from her resting place in Coimbra and taken to Alcobaça where it was reburied in the royal monastery. Peter had two tombs constructed, one for each of them, so they would see each other when rising at the Last Judgment. The tombs show Peter and Inês facing each other, with the words "Até o fim do mundo..." ("Until the end of the world...") inscribed on the marble. Peter was also the father of Ferdinand I of Portugal and John I of Portugal. John was the Master of the military order of Avis, and he would become the founder of the Avis dynasty after the 1383–85 Crisis.

Question: Who is the father of Peter I of Portugal?
Answer: Afonso IV of Portugal.
The Brave.