Our notices of Guidobaldo become ever more barren. In 1565 the armament of Sultan Solyman against Malta spread consternation throughout Western Europe, and, by desire of Philip II., the Duke of Urbino sent four or five thousand troops to aid in the defence of the knights. Prince Francesco Maria asked leave to accompany the expedition, but his father, considering his time better bestowed in visiting courts, sent him in this year to Madrid, with commission to recover a long arrear of his own military allowances. In this he was successful, but the sum scarcely sufficed to clear the expenses of his journey. Particulars of this visit, and of his marriage in 1571, will be told from his own pen in next chapter. But there was no lukewarmness on his father's part on the question of the Cross against the Crescent. After the Prince returned from the naval action off Lepanto, which will also be narrated from his Autobiography, Guidobaldo prepared a Discourse on the propriety of a general war against the Turks, the means of conducting the proposed campaign with due regard to the security of Italy, the preparation of adequate munitions, and the best plan for carrying the seat of war into the enemy's country. It is unnecessary to dwell upon a matter now so completely gone by: the paper emanates from a mind capable of enlarged views, and fully conversant with the belligerent resources and general policy of his age, as well as experienced in military operations.[63] [Footnote 63: Vat. Ottob. MSS. No. 2510, f. 201.] The _Relazioni_ of the Venetian envoys supply us with some notices of Urbino about this time, and prove that the Duke's expenses were very great, partly from frequent calls upon his hospitality by visitors of distinction, but still more from his maintaining separate and costly establishments for himself, the Duchess, the Prince, and the Princess.[64] Mocenigo estimates his income from imposts, monopolies, and allodial domains, at 100,000 scudi; adding that, "should he think proper to burden his people, this sum might unquestionably be greatly augmented, but, choosing to follow the custom of his predecessors, in making it his chief object to preserve the affection of his subjects, he is content to leave matters as they are, and live in straits for money."[65] He also tells us that, though poor in revenues, he was master of his people's affections, who on an exigency would place life and substance at his disposal. The accuracy of these impressions is in some degree impugned by what we are now about to relate. [Footnote 64: That of Mocenigo, 1570, is printed by Vieussieux, second series, vol. II., p. 97, and in the _Tesoro Politico_, II., 169; that of Zen or Zane, 1574, in the same volume of Vieussieux, p. 315.]