Interea Messenii, cum virtute non possent, per insidias expugnantur. dein cum per annos octoginta gravia servitutis verbera, plerumque et vincula ceteraque captivitatis mala perpessi essent, post longam poenarum patientiam bellum restaurant. Lacedaemonii quoque eo conspiratius ad arma concurrunt, quod adversus servos dimicaturi videbantur. itaque cum hinc iniuria, inde indignitas animos acueret, Lacedaemonii de belli eventu oraculo Delphis consulto iubentur ducem belli ab Atheniensibus petere. porro Athenienses, cum responsum cognovissent, in contemptum Spartanorum Tyrtaeum, poetam claudum pede, misere, qui tribus proeliis fusos eo usque desperationis Spartanos adduxit, ut servos suos ad supplementum exercitus manumitterent hisque interfectorum matrimonia pollicerentur, ut non numero tantum amissorum civium, sed et dignitati succederent. sed reges Lacedaemoniorum, ne contra fortunam pugnando maiora detrimenta civitati infligerent, reducere exercitum voluerunt ni intervenisset Tyrtaeus, qui composita carmina exercitui pro contione recitavit, in quibus hortamenta virtutis, damnorum solacia, belli consilia conscripserat. itaque tantum ardorem militibus iniecit, ut non de salute, sed de sepultura solliciti tesseras insculptis suis et patrum nominibus dextro bracchio deligarent, ut, si omnes adversum proelium consumpsisset et temporis spatio confusa corporum liniamenta essent, ex indicio titulorum tradi sepulturae possent. cum sic animatum reges exercitum viderent, curant rem hostibus nuntiare; Messeniis autem non timorem res, sed aemulationem mutuam dedit. itaque tantis animis concursum est, ut raro umquam cruentius proelium fuerit. ad postremum tamen victoria Lacedaemoniorum fuit.
(Justinus, Epitome Pompeii Trogi 3.5)

Meantime the Messenians, who could not be conquered by valour, were reduced by stratagem. For eighty years they bore the severe afflictions of slaves, as frequent stripes, and chains, and other evils of subjugation; and then, after so long an endurance of suffering, they proceeded to resume hostilities. The Lacedaemonians, at the same time, ran to arms with the greater ardour and unanimity, because they seemed to be called upon to fight against their own slaves. While ill-treatment, therefore, on the one side, and indignation on the other, exasperated their feelings, the Lacedaemonians consulted the oracle at Delphi concerning the event of the war, and were directed to ask the Athenians for a leader to conduct it. The Athenians, learning the answer of the oracle, sent, to express their contempt of the Spartans a lame poet, named Tyrtaeus; who, being routed in three battles, reduced the Lacedaemonians to so desperate a condition, that, to recruit their army, they liberated a portion of their slaves, promising that they should marry the widows of those who were slain, and thus fill up, not merely the number of the lost citizens, but their offices. The kings of Sparta, however, lest, by contending against fortune, they should bring greater losses on their city, would have drawn off their army, had not Tyrtaeus interposed, and recited to the soldiers, in a public assembly, some verses of his own composition, in which he had comprised exhortations to courage, consolations for their losses, and counsels concerning the war. By this means he inspired the soldiers with such resolution, that, being no longer concerned for their lives, but merely for the rites of burial, they tied on their right arms tickets, inscribed with their names and those of their fathers, that if an unsuccessful battle should cut them off, and their features after a time become indistinct, they might be consigned to burial according to the indication of the inscriptions. When the kings saw the army thus animated, they took care that the state of it should be made known to the enemy; the report, however, raised in the Messenians no alarm, but a correspondent ardour. Both sides accordingly encountered with such fury, that there scarcely ever was a more bloody battle. But at last victory fell to the Lacedaemonians. (tr. John Selby Watson)