By this time, the Portuguese throne was disputed by several claimants. Among them were Catherine, Duchess of Braganza (1540–1614), her nephew the 11 years old Ranuccio I Farnese, Duke of Parma, King Philip II of Spain and the Prior of Crato himself. The Duchess was later named as the legitimate heir, after her descendants obtained the throne in 1640 (through King John IV of Portugal), but at that time, she was one of possible heirs. According to feudal custom, her late older sister’s son Ranuccio, an Italian, was the closest heir, followed by the Duchess herself, and only after them, King Philip. Philip II descended from Manuel I through a female line. As for António, although King Manuel I’s grandson in male line, he was an illegitimate grandson.
António, relying on the popular hostility to a Spanish ruler (even if Philip’s mother was Portuguese), presented himself as an alternative candidate to King Philip II. He endeavoured to prove that his father and mother were married after his birth but no evidence of the marriage could be found at the time (and is still question of debate). António’s claim, which was inferior to those of Philip II and the Duchess of Braganza, was not supported by the nobles or gentry. His partisans were drawn almost exclusively from the inferior clergy, the peasants and workmen. Moreover, Philip managed to bribe the upper classes of Portugal with gold from the Americas which ensured the success of his pursuit of the Portuguese crown. For them, the idea of a personal union of the crowns with Spain would be highly profitable for Portugal, which had been experiencing an economic downturn at the time, and would maintain formal independence as well as authonomous adminstration (in Europe and the empire).