This chapter explores the relationship between Dutch and Spanish conceptions of civil power and monarchy. The political theory of Hugo Grotius was the culmination of the close link between Spanish and Dutch political thought. The Dutch rebels imputed a Spanish conception of monarchy to Philip II as being founded on the claim to absolute power. In conformity with trends elsewhere in Europe, Castilian authors had started during the late medieval period to include the concept of absolute power in their theories of monarchy. Dutch authors recognised the political and intellectual connections between liberty and civil power from the beginning of their protest against the policies of Philip II. In the clarity and forcefulness of Grotiuss argument the distinction between Spanish tyranny and Dutch liberty, which had dominated Dutch political thought since the 1560s, evolved into an opposition between kingship and republic.