ABSTRACT
In 1609, the Dutch jurist Hugo Grotius noted that 'because the sea is fluid and ever changing, it cannot be possessed. This chapter seeks to explore the origins of a concept which was always an overstatement of ambitions, to the point that it is difficult to understand how it ever came into being. The medieval roots of claims to sovereignty or overlordship of the sea lie in the struggle of medieval monarchs to assert their superiority over their noble vassals. There were practical implications of the English monarchs' claim to overlordship in their territorial waters. The confrontation with Philip II's Spain in the last two decades of the sixteenth century catalysed on the part of enterprising Englishmen developed greater ambitions for their monarch and their country, and introduced the quantum leap in the interpretation of the 'command of the sea'. And this was inspired by the rediscovery of Thucydides and his idea of 'thalassokratia'.
