The forty years after the conclusion of the Treaty of Copenhagen in 1660 saw no English naval activity in the Baltic, but since there was plenty of diplomatic activity, this was largely a matter of luck, even inadvertence. It was as if having once intervened it was expected that the English ships would return to the sea. As a result, given the naval power England disposed of, in the end the navy was driven to take part in direct Baltic affairs. The period saw two more wars with the Dutch, and the Baltic lay at the back of both.

The new English monarchic regime after 1660 made preliminary treaties with Denmark, Sweden and Brandenburg, none of which amounted to much, but they did indicate that England was now seen as a regular player in the Baltic arena. The crucial relationship, however, as before 1660, was with the Dutch. King Charles II appears to have early decided that he should initiate a new Dutch war. If he was to do so, then the relationship with Denmark became important. So the preparations for the war included diplomatic attempts to secure a Danish alliance.

The war was begun by a series of pre-emptive English conquests – New Amsterdam, a string of West African forts, and the capture of ‘enemy’ merchant ships at sea – until by March 1665 the Dutch had been provoked enough to declare war. The preparations on both sides of the North Sea produced two great naval fleets. Diplomacy meanwhile centred on the Elector of Brandenburg, Frederick William, who linked his land with Denmark and several small North German states into an alliance with the Dutch. So England had no friends. Nor, as it happened, did the Dutch. The Elector’s alliance was a fragile thing, and English envoys set out to work on the member who, apart from the Dutch Republic, was seen as the most awkward and perhaps the most likely to defect. This was Frederik III of Denmark.

These rulers – Frederik of Denmark, Frederick William of Brandenburg, the ruling Regency of Sweden – had taken advantage of the several peace treaties after 1660 to clamp their grips firmly on their countries’ governments. Frederick William skilfully removed the privileges of the towns and brought his government into an alliance with the nobility as against the towns and the peasantry.