Probably the most striking event of this brief reign, which in many ways resembles a politically tumultuous interregnum, was the legal dispute between the various candidates for the crown of Portugal, triggered and raised by the cardinal-king himself. In fact, although Philip II did not formally respond to the request because he considered his rights to be indisputable and not subject to scrutiny by any court, the fact is that, for some time, the various candidates were able to make arguments in their favour, mobilising jurists and the peninsular and French universities to do so. In the absence of clear rules of succession, an unusual legal and political debate took place. Apart from the hypothetical and unfounded candidacy of Catarina de Medicis, there were five candidates. All of them were descended from King Manuel I, whose first-born line of succession had been extinguished with the death of King Sebastião: Filipe II, as the son of the monarch's first-born daughter, Isabel; Manuel Felisberto, Duke of Savoy, as the son of the former's immediate sister, Beatriz; Rainuncio, Duke of Parma, as the son of the eldest daughter with descendants of Prince Duarte, Duke of Guimarães and the only surviving male son with descendants of King Manuel; Catherine, Duchess of Bragança by marriage, the younger sister of the former's mother; and, finally, António, Prior of Crato, bastard son of Prince Luís, also a son of King Manuel. For political and proximity reasons, only the candidacies of Filipe II and D. Catarina would be seriously supported, while the candidacy of the prior of Crato still had important support, although with little basis in law, precisely the area in which the cardinal-king endeavoured to see the issue settled.
It's impossible to summarise in a few lines all the allegations mobilised by the two candidacies, which did indeed make systematic use of legal arguments. In Catherine's favour was the fact that, although she was a woman, she would accede to the throne by the right of her father, who, in the previous generation, would unquestionably have precedence over all women. This was called the right of representation, in other words, Catherine would represent her father's right. In Philip II's favour was the fact that, although he had a female line, he was a man and the closest male descendant to the aforementioned monarch. The arguments rarely revolved around the exclusion of women (generally without expression in the peninsular law of Portugal or Castile), but rather about whether the law of the people or Roman law applied, about whether in kingdoms one succeeded as an heir, about the analogies between succession in the kingdom and Mental Law, etc. In fact, there was a legal vacuum, so it was debatable who was entitled to succession in the kingdom, a question that would be clarified and rectified by later law. But it should be noted that, in the light of some aspects of the law that were enshrined later, the Duke of Savoy's candidacy had far more arguments than the support he was given at the time.
