Behind this there was another mysterious negotiation going on, relating apparently to a marriage between Charles's eldest daughter Mary Stuart to Prince Baltasar Carlos, both of whom were children of tender years. Many close conversations on the subject took place between Hopton, as the personal mouthpiece of King Charles, and Philip and his minister. The constant claims and complaints of the English merchants and shipmasters of Spanish extortion annoyed Hopton almost as much as Olivares, because they introduced an element of trouble in these loving confabulations. But Hopton, though zealous to serve his King, was clearly ill at ease, as well he might be, for it was a dangerous business for Charles to receive a big money subsidy from SPain, as was proposed, and to turn the arms of England against the Protestants. Hopton goes so far, indeed, as to say in his letters to Windebank that he is not in favour of the subsidy, but that King Charles should fit out a fleet at his own expense against the Dutch. This will, he says, be easier, and will leave Charles more free and able to bring the Dutch to reason. But, he continues, if the matter is undertaken at all, it must be seen through to the end, or Holland will wax too insolent to be borne. {277} Long discussions with the Council of State and with Olivares kept Hopton busy in Madrid for months; the while the great betrayal proposed was kept from the Secretary of State and all the responsible ministers in England, a good foretaste of the policy that led Charles Stuart to ruin and the block. To the official Secretary of State, Hopton had much to say about the great preparations being made in Spain for war, but no word about the secret plan for England to join in it on the Catholic side. Great loans and levies are constantly being raised, he reported in April 1634.