When this letter reached Caron, a dramatic change in the English policy had taken place to the advantage of the Netherlands. The negotiations with Spain for the restitution of the Palatinate had broken down. Philip IV and Olivares had never intended to purchase the friendship of England at such a price, and the marriage prospect, on which for so many years his heart had been set, had to be reluctantly abandoned by King James. 'I like not', he said, 'to marry my son with a portion of my daughter's tears.'
The return of the Prince of Wales and the Duke of Buckingham, October 5, angry at the treatment accorded to them at Madrid, led to the overthrow of the party at Court which had favoured a Spanish alliance. Parliament was summoned, and Buckingham in advocating an anti-Spanish policy found himself for once a popular favourite. Pressed by his son, by Buckingham, by Parliament, and by public opinion, the aged King with a heavy heart saw himself compelled to abandon his cherished scheme of recovering the Palatinate by peaceful negotiations, and to take steps for armed intervention. The States-General, on seeing the turn that events were taking, wisely determined to send another embassy to London to take advantage of the opportunity for concluding the wished-for offensive and defensive alliance between England and the United Provinces. There was this time no delay in drawing up the instructions, and Aerssen and Joachimi, the two best men they could have chosen, departed on their mission February 24.
There can be little question that the moving cause for the sending of this embassy with such unusual dispatch is to be found in an interview between Sir Dudley Carleton and Prince Maurice, which the former records in a letter to the Duke of Buckingham dated December 9, 1623.
'I have thought fit', wrote the ambassador, 'to set down at large (whilst it is fresh in my memory) an opportunity as properly given unto me this day by the Prince of Orange (who is the only person of power and confidence we have here to treat withal) as I hope your Grace will think it seasonably taken.'
Some business at the Council of State, at which both were present, having been got through more quickly than was expected, Maurice, so Carleton informed his correspondent,