The imminent end of the Avis dynasty stimulated the various genealogical branches of the monarchy to claim the Portuguese crown. Six candidates presented themselves: from Portugal, Catarina, the Duchess of Bragança, and Antônio, Prior of Crato, both grandchildren of King Manuel by the paternal line; Philip II, King of Spain, and Manuel Felisberto, Dule of Savoy, both grandsons of Venturoso (as King Manuel was known), by the maternal line; Rainúncio Farnese, son of the Prince of Parma, great-grandson of Manuel, as well as Catarina de Medici, through a remote connection with Afonso III, who died in 1279. The number of candidates and the stature of some of them indicates the importance of Portugal in the political game at the time, the various negotiations this produced, and the roles played by the diplomatic representation of the claimants in the various European courts.
Following the disappearance of King Sebastião at the Battle of Alcácer Quibir in August 1578, Cardinal Henrique assumed the throne of Portugal. The last of the Avis dynasty, in his short two year reign the Cardinal faced the many different types of pressure: governing in the middle of the commotion of the disaster; administering the ransoming of a large part of the nobility imprisoned in Morocco; and, most seriously mediating, the delicate succession crisis which began as soon as the rumors of the disaster reached Europe. Acting as conciliator and judge, as well as administrating the various succession demands and projects, he worked directly with Rome, aiming to obtain his authorization for his marriage, seen as a necessary personal sacrifice to guarantee the legitimate and natural succession for the kingdom.