*36* As for war, humane laws touching it are drawn up in the fetial code of the Roman People under all the guarantees of religion; and from this it may be gathered that no war is just, unless it is entered upon after an official demand for satisfaction has been submitted or warning has been given and a formal declaration made. Popilius was general in command of a province. In his army Cato's son was serving on his first campaign. When Popilius decided to disband one of his legions, he discharged also young Cato who was serving in that same legion. But when the young man out of love for the service stayed on in the field, his father wrote to Popilius to say that if he let him stay in the army, he should swear him into service with a new oath of allegiance, for in view of the voidance of his former oath he could not legally fight the foe. So extremely scrupulous was the observance of the laws in regard to the conduct of war. *37* There is extant, too, a letter of the elder Marcus Cato to his son Marcus, in which he writes that he has heard that the youth has been discharged by the consul,[I] when he was serving in Macedonia in the war with Perseus. He warns him, therefore, to be careful not to go into battle; for, he says, the man who is not legally a soldier has no right to be fighting the foe. [I] Lucius Aemilius Paulus (B.C. 168). XII. Equidem etiam illud animadverto, quod, qui proprio nomine perduellis esset, is hostis vocaretur, lenitate verbi rei tristitiam mitigatam. Hostis enim apud maiores nostros is dicebatur, quem nunc peregrinum dicimus. Indicant duodecim tabulae: AUT STATUS DIES CUM HOSTE, itemque: ADVERSUS HOSTEM AETERNA AUCTORITAS. Quid ad hanc mansuetudinem addi potest, eum, quicum bellum geras, tam molli nomine appellare? Quamquam id nomen durius effecit[32] iam vetustas; a peregrino enim recessit et proprie in eo, qui arma contra ferret, remansit. *38* Cum vero de imperio decertatur belloque quaeritur gloria, causas omnino subesse tamen oportet easdem, quas dixi paulo ante iustas causas esse bellorum. Sed ea bella, quibus imperii proposita gloria est, minus acerbe gerenda sunt. Ut enim cum civi aliter contendimus, si[33] est inimicus, aliter, si competitor (cum altero certamen honoris et dignitatis est, cum altero capitis et famae), sic cum Celtiberis, cum Cimbris bellum ut cum inimicis gerebatur, uter esset, non uter imperaret, cum Latinis, Sabinis, Samnitibus, Poenis, Pyrrho de imperio dimicabatur. Poeni foedifragi, crudelis Hannibal, reliqui iustiores. Pyrrhi quidem de captivis reddendis illa praeclara: #Ennius, Ann. VI, Vahlen^2, xii, 194-201#