The sixteenth-century splits in the Christian Church in Europe fundamentally transformed relations among the ruling Atlantic powers. However, the confessional splintering and increasing hostility and aggression did not upset economic relations in areas where lucrative trading already existed. Current historiography insists on the cross-confessional nature of European trading at that time, starting with the legal overthrow of the canonical ban on trading with enemies and infidels, promoted by theorists and legal experts of the Spanish and Portuguese empires. As a matter of fact, the sixteenth-century Spanish Habsburgs' trade wars against Protestant states never shut off all trade; trade continued, particularly in strategic areas that depended on supplies from abroad. Indeed, in these areas international trade with enemies of the Habsburgs was often legitimized and regulated.

Often, though, illegal trade only became more widespread throughout Europe as trade embargoes between countries increased. These barriers had varying effects for the Dutch, English, French and Spanish. Regarding the Spanish-Dutch conflict, some scholars maintain that embargoes were largely effective while others point out their limited impact because merchants found alternative channels for trading by circumventing the restrictions. This chapter examines both angles, revealing how the permeable nature of religious identities contributed to the failure of such embargoes.

This essay concentrates on the north of Spain, a region whose economy was dependent on continuing trade with Protestant nations in Europe.