Protestantism was supreme at home, and abroad it was decisive in questions of peace and war.

The leaders of the Long Parliament, who encouraged the friendly relations with Spain, and carried on the war against Holland with the utmost energy, had already by so doing given offence to the Protestant Churches. A common danger to the Protestant creed seemed to be imminent when the two most powerful states which adhered to it, the two Protestant Republics, were plunged in war, and were weakening each other.

Peace was as much for the interests of the Protector as for those of England. It gratified the Protestant sympathies of the nation. The English Presbyterians joyfully welcomed it. It was under the influence of these sentiments that the Swedish negotiations had been entered upon and the peace with Denmark concluded.

The example of Germany showed how injurious to the common cause of Protestantism were the feuds of the various denominations, and the English government in consequence gave renewed support and attention to the efforts of the great apostle of Protestant union, John Dury. He was attached to the embassy which was now sent to Switzerland, and which had in view also the relations with Germany and the learned there, especially George Calixtus at Helmstadt.