Peter I (Portuguese: Pedro I, ; 8 April 1320 – 18 January 1367), called the Just (o Justiceiro) 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. Early life In 1328, Peter's father, Afonso IV arranged for the marriage of his eldest daughter, Maria, to Alfonso XI of Castile. However, soon after their marriage Alfonso began a long affair with the beautiful and newly widowed Leonor de Guzman. Maria bore Alfonso a son in 1334, who ultimately became Peter of Castile, but after the Castilian king refused to end his affair Maria returned home to Portugal in 1335. Alfonso had been married once before, to his cousin's daughter, Constanza Manuel (granddaughter of James II of Aragon). Alfonso had the marriage annulled in 1327, after only two years, to clear the way for marriage to Maria. This angered his cousin Juan Manuel, Prince of Villena, a powerful Castilian aristocrat, and for two years Juan Manuel waged war against the Castilians - who had kept his daughter Constanza hostage - until Bishop John del Campo of Oviedo mediated a peace in 1329. Afonso, now enraged by the infidelity and mistreatment of his daughter Maria, forged an alliance with Juan Manual by marrying his son and heir, Peter, to Constanza. When Constanza arrived in Portugal in 1340, Inês de Castro, the beautiful and aristocratic daughter of a prominent Galician family (with links albeit through illegitimacy, to the Portuguese and Castilian royal families), accompanied her as her lady-in-waiting. Peter soon fell in love with Inês, and the two conducted a long love affair that lasted until Inês's murder in 1355. Constanza died in 1349, following childbirth complications. The scandal of Peter's affair with Inês, and its political ramifications, caused Afonso to banish Inês from court after Constanza died. Peter refused to marry any of the princesses his father suggested as a second wife; and the king refused to allow his son to marry Inês as Peter wanted. The two aristocratic lovers began living together 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