Abstract

The Catholic Monarchy is the short-lived dynastic union (1580-1640) between the kingdoms of Spain and Portugal. By returning on the legal, political and pragmatic foundations of this empire which cannot be called Empire (because this name belongs to the Holy Roman Empire of the cousins of Vienna), the article tries to seize better the internal functioning of this heterogeneous political set, by adopting two points of view: that of America (how the notion of Catholic Monarchy is understood in the reynos, far from Madrid and Lisbon) and that of Rome (how Holy See reaches - or not - to exist in the heart of this space). It emerges from it that the pope and the Catholic King are natural allies (around the Roman Christianity) but not objectives (their purposes do not match), and that Rome and Mexico as well picture themselves not as margins of the Catholic Monarchy, but as real centers