The sea wars in the Caribbean since Columbus’ voyages had involved one major power and its ships – Spain – beset by a cloud of small ships, who were only occasionally accompanied by recognised war vessels, and rarely in larger groups than two or three. Among all the French and English ships and fleets which harassed the Spaniards in the Caribbean it is impossible to classify most of them as sent out by royal decree. Privateers at times had a licence to rob from the ships of specific countries, but they rarely restricted themselves to their designated victims; and they could never be accused of acting in any sort of official capacity. Some expeditions did lean towards being official – such as Drake's voyage in 1585–1586, or that with Hawkins ten years later, but even these were conducted in the same informal way as any privateering raiding voyage, because the commander was himself a privateer. The earl of Cumberland might have had Queen Elizabeth's permission to harass Spanish settlements, but he was not conducting a maritime campaign in any recognisable sense. Any such expedition normally avoided any contact with Spanish warships; they were all raids, not aiming at deliberate conquests, though that is not to say that the thought of conquest was not there, or voiced.

Hence it has been difficult to justify the inclusion of the previous chapters in a book which aims to discuss the role of the British Navy in West Indian waters. On the other hand, it was only as a result of the activities of the privateers, especially in wartime, that Spanish power had been forced to concentrate into certain areas, and to effectively abandon others. This was the necessary preparation for the permanent intrusion of non-Spanish colonies into the Spanish-claimed territory. It was widely understood that Spain claimed exclusive rights over far more of America than it physically occupied, and that it would normally oppose in arms any such activity, whether by privateers, colonists, hostile armies, or powerful traders or settlers; also that the Spanish claim to exclusive possession was contested by every other state in Europe with a maritime capability.