And in that the most high and excellent Prince and most mighty Lord, the King Don Affonso the Vth (who at the time of the writing of this book reigned in Portugal, by the grace of God, whose reign may God in his mercy increase in length and in virtues), in that he, I say, saw and knew the great and very notable deeds of the Lord Infant Don Henry, Duke of Viseu and Lord of Covilham, who was his highly-valued and beloved uncle, and in that the said deeds appeared to him so noteworthy among the many actions of Christian princes in this world--it seemed to him a wrong thing not to have some authentic memorial of the same before the minds of men. And this most of all because of the great services which the said Lord had ever rendered to past kings, and the great benefits which by his efforts the Prince's countrymen had received. For these reasons the King bade me engage in this work with all diligence, for although great part of his other actions are scattered through the Chronicles of the Kings of his day, as, for instance, what he did when the King Don John, his father, went to take Ceuta,[N2] and when on his own account he went with his brothers and many other great lords to raise the siege of the aforesaid town, and afterwards when in the reign and by the command of the King Don Edward of glorious memory, he attacked Tangier, where were done many very notable deeds, which are mentioned in his history, yet all that followeth was done by his ordinance[C] and mandate, not without great expense and trouble, all which is truly to be set down to his account. For though in all kingdoms men compile general Chronicles of their Kings, they do not fail also to write separately of the deeds of some of those Kings' vassals, wherever the greatness of the same is notable enough to warrant such especial mention--as was done in France in the case of Duke John, Lord of Lançam,[N3] and in Castille in the matter of the deeds of the Cid Ruy Diaz,[N4] and in our own kingdom in the story of the Count Nunalvarez Pereira.[N5] And with this Royal Princes ought to be not a little contented, for so much the more is their honour exalted as they have seigniory over greater and more excellent persons; for no Prince can be great, unless he rule over great men; nor rich, unless he rule over the wealthy. For this cause said the virtuous Roman Fabricius, that he would rather be lord over those who had gold, than have gold himself. [Footnote C: _I.e._, all that follows in this book was done by Henry's ordinance, etc.]