What followed forms one of the strangest chapters in the history of diplomacy. De Witt had all this time been keeping up, in complete secrecy, a private correspondence with the leading envoy, his confidant Van Beverningh. Through Van Beverningh he was able to reach the private ear of Cromwell, and to enter into clandestine negotiations with him. The council-pensionary knew well the hopelessness of any attempt to get the assent of the States-General to the proposed exclusion, even in a secret article. Van Beverningh was instructed to inform Cromwell of the state of public feeling on this point, with the result that the Protector gave the envoy to understand that he would be satisfied if the Estates of Holland alone would affirm a declaration that the Prince should never be appointed stadholder or captain-general. Whether this concession was offered by Cromwell proprio motu or whether it was in the first instance suggested to him by De Witt through Van Beverningh is unknown. In any case the council-pensionary, being convinced of the necessity of peace, resolved to secure it by playing a very deep and dangerous game. Not only must the whole affair be kept absolutely from the cognisance of the States-General, but also De Witt was fully aware that the assent of the Estates of Holland to the proposed exclusion article could only be obtained with the greatest difficulty. He was to prove himself a very past master in the art of diplomatic chicanery and intrigue.