“But to exercise the intellect the prince should read histories, and study there the actions of illustrious men, to see how they have borne themselves in war, to examine the causes of their victories and defeat, so as to avoid the latter and imitate the former; and above all do as an illustrious man did, who took as an exemplar one who had been praised and famous before him, and whose achievements and deeds he always kept in his mind, as it is said Alexander the Great imitated Achilles, Caesar Alexander, Scipio Cyrus. And whoever reads the life of Cyrus, written by Xenophon, will recognize afterwards in the life of Scipio how that imitation was his glory, and how in chastity, affability, humanity, and liberality Scipio conformed to those things which have been written of Cyrus by Xenophon. A wise prince ought to observe some such rules, and never in peaceful times stand idle, but increase his resources with industry in such a way that they may be available to him in adversity, so that if fortune changes it may find him prepared to resist her blows.”
Source: Niccolò Machiavelli (W.K. Marriott, translator), The Prince, Chapter XIV