At another time, we find him conducting negotiations with Navarre;[316] and then, again, carrying on a correspondence with his sister, the regent of Portugal, for the purpose of having his grandson, Carlos, recognized as heir to the crown, in case of the death of the young king, his cousin. The scheme failed, for it would be as much as her life was worth, the regent said, to engage in it. But it was a bold one, that of bringing under the same sceptre these two nations, which, by community of race, language, and institutions, would seem by nature to have been designed for one. It was Charles's comprehensive idea; and it proves that, even in the cloister, the spirit of ambition had not become extinct in his bosom. How much would it have rejoiced that ambitious spirit, could he have foreseen that the consummation so much desired by him would be attained under Philip![317] [Sidenote: HIS INTEREST IN PUBLIC AFFAIRS.] But the department which especially engaged Charles's attention in his retirement, singularly enough, was the financial. "It has been my constant care," he writes to Philip, "in all my letters to your sister, to urge the necessity of providing you with funds,--since I can be of little service to you in any other way."[318] His interposition, indeed, seems to have been constantly invoked to raise supplies for carrying on the war. This fact may be thought to show that those writers are mistaken who accuse Philip of withholding from his father the means of maintaining a suitable establishment at Yuste. Charles, in truth, settled the amount of his own income; and in one of his letters we find him fixing this at twenty thousand ducats, instead of sixteen thousand, as before, to be paid quarterly and in advance.[319] That the payments were not always punctually made may well be believed, in a country where punctuality would have been a miracle.