List of heirs to the Portuguese throne
This is a list of the individuals who were, at any given time, considered the next in line to inherit the throne of Portugal, should the incumbent monarch die. Those who actually succeeded (at any future time) are shown in bold. Stillborn children and infants that died on the same day they were born are not included. For much of Portugal's early history, there was no definite succession law, and potential heirs at any given time, especially when the reigning king had no son, may be partly a matter of conjecture. The  traditional Portuguese dynastic division of the monarchs is shown as breaks in the table below. House of Burgundy (1139–1383). Although King Fernando I had intended his daughter Beatriz to succeed (with her mother Queen Leonor as regent), she was an unpopular choice due to fears that her husband King John I of Castile would control the kingdom. After the 1383–1385 Crisis, Fernando's illegitimate half-brother João, Grand Master of the Order of Aviz became king. House of Aviz (1385–1580). After Cardinal-King Henrique's death, the throne was claimed by several individuals, including António, Prior of Crato, an illegitimate  grandson of King Manuel I, and Infanta Catarina, Duchess of Braganza, a legitimate granddaughter of King Manuel I. Eventually King Philip II of Spain, undoubtedly the most powerful claimant, succeeded in becoming king of Portugal. House of Habsburg (1580–1640). Note: All Princes of Portugal and infantes from the House of Habsburg were also Princes of Asturias and infantes of Spain respectively.