How much unity had the reigns of Ferdinand and Isabella brought to Spain by 1516?

Answer 1

The union between the Spanish kingdoms of Castile and Aragon was almost merely dinastic until 1715. This means that the had their own laws, parliaments (Cortes) , armies etc. For exemple, there were commercial frontiers between the kingdoms. Anywhere, this kind of organization there wasn't strange during the "Ancien Regime" in Europe despite the centralization eforts in XVIIth and XVIIIth centuries (specially in France). In the case of Spain, the first attemp of "centralization" was made in 1640. It's is known as "Unión de Armas" and the goal was to make an united army with proportional men for each kingdom, but it was hardly (an bloody) contested by the Ctalan aristocracy. Later, during the Spanish Succesion War (1700-1715), the kingdoms of the Aragonese crown supported the Austrian candidate who later lost the war. As punishment, the new king, Philip of Anjou (Philip V of Spain) suspended the "fueros" (the laws that granted the autonomy of the kingdoms and even cities in Spain) of these kingdoms. But the spanish union as modern nation state is reached with the liberal constitution of 1812. The XIXth and XXth centuries will be a time of constant tensions between the centralistic and the partisans of a decentraliced state, defending the "fueros" in the early XIXth century and defending the federalism and even seperatism after the lately XIXth century.