Some few score of years before these events, the Aragonese had rebelled against Philip II for reasons similar to those for which the Scots rebelled against Charles I. The pressure of the ecclesiastical and temporal rule as exercised by that sovereign had made the Aragonese anxious for their ancient liberties: the Inquisition was as much hated by them as the High Commission by the Scots; and a trivial circumstance had sufficed to cause the nobles, the hidalgos, and the towns to revolt in quick succession. But Philip II had arrayed against the Aragonese the power of his principal state of Castile, to the position of which they feared to be reduced, had recovered their obedience by force, had still more narrowly restricted their ancient liberties, and had established the royal authority more firmly than any of his predecessors had ever succeeded in doing.

The cause of the Scots involved yet more serious issues than that of the Aragonese. If the Aragonese had been victorious, they would only have revived within narrow territorial limits a representative Catholic constitution, according to the ideas of the middle ages. The Scots on the other hand repudiated everything which reminded them of the old hierarchy and its alliance with the crown: they laid claim on religious grounds to a political freedom such as had never yet existed in the world.

So much the more did Charles I believe himself entitled to put an end to this movement by force of arms.