December 16, 1653

Oliver Cromwell ruled England between Regicide and  Restoration. It was England's only historical interlude without a monarch. They had, though, a ruler, though one who had some parliamentary legitimacy, in Cromwell. His actions often seemed opaque to his contemporaries. 

The famous historian of 17th century England, Christopher Hill, writes of the intersection between ideology and psychology, in his Oliver Cromwell 1658-1958, (1973):

...[T]he clue to Cromwell's delays and sudden violent actings is to be found in the famous maxim, "Trust in God and keep your powder dry." Because one is fighting God's battles, one must be more, not less, careful to run no risk of failure...In politics... since the cause was the Lord's , every avenue must be explored, every contingency foreseen, before Cromwell committed himself to any course of action...When he had completed his reconnaissance and was sure of his dispositions then he struck hard and with confidence he was acting righteously. But to contemporaries, 'waiting on the Lord,' might seem like waiting to see which way the cat would jump.

Again this is a paradox of Puritanism. "Trust in God and keep your powder dry," perfectly expresses that tension between predestination and free will which lay at the heart of Calvinism.

It was on December 16, 1653 that Cromwell assumed the title of Lord Protectorate of a Commonwealth that consisted of England, Scotland, and Ireland, the visible effect of previous actings. 

Students of English history will recall that with the death of Cromwell, the best idea, for a period, was to have Cromwell's son succeed him, a fellow incapable of acting period.  This was not destined to last.  But the Interregnum period was to define a peculiar kind of English tolerance for centuries to come, almost like a vaccination against continental excesses.