Silence a horse by binding the tail
That a horse may not neigh. Horses neigh, some as a threat, others when they have taken only the smell from the females. Both their voice and their silence are useful. When they charge they are taught to shout together into fear with the fellow-soldiers; when they lie in ambush, to hide together with them. But this artificial thing is blunted still more either by the season of the year or by erotic nature.
Aristomenes the Messenian took Lacedaemonians who were lying in ambush when their horses neighed, himself leading a mare. And again he himself set his ambush without danger, his horses having been forced to be silent by a station of Spartan mares. The Messenian's stratagem remains remembered. So whether a man would go through a place infested with brigands, or would sit a cavalry ambush under the enemy, let him do what will be shown. This is not only a work and invention of old Greek generals: the Parthians also lead their own horses silent into the fights in this way.
With a well-twisted sinew the tail of the horse is bound tight above the hair, so that the bond sinks far into the surface. By the tension of the binding the horse, being in pain, keeps the same spirit and speed, but holds back only the voice, even if the compelling occasion is love.
Greek
1.7 Μὴ χρεμετίσαι ἵππον Ἵπποι χρεμετίζουσιν, οἳ μὲν ἀπειλοῦντες, οἳ δὲ τὴν ἀπὸ θηλειῶν μόνον λαβόντες ὀδμήν. Χρήσιμος δὲ αὐτῶν καὶ ἡ φωνὴ καὶ σιωπή. Ὁπότε μὲν γὰρ <ἐφορμῶσιν>, εἰς φόβον συναλαλάξαι τοῖς συστρα τιώταις διδάσκονται, ὅτε δὲ λοχῶσιν, αὐτοῖς συλλαθεῖν. Ἀλλὰ γὰρ τὸ τεχνητὸν τοῦτο ἢ ὥρα ἔτους ἢ ἐρωτικὴ φύσις ἐπὶ μᾶλλον ἀμβλύνει. Ἀριστομένης γοῦν ὁ Μεσσήνιος Λακεδαιμονίους εἷλεν λοχῶντας, τῶν ἵππων αὐτοῖς χρεμετισάντων, αὐτὸς θηλείας ἄγων. Καὶ πάλιν αὐτὸς τὴν ἐνέδραν κατέστησεν ἀκίνδυνον, τῶν ἵππων αὐτοῦ ἀναγκασθέντων σιωπᾶν Σπαρτιατῶν ἵππων θηλειῶν στάσει. Τὸ τοῦ Μεσσηνίου στρατήγημα μένει μεμνημένον. Εἴτ' οὖν λῃστευόμενόν τις διΐοι χωρίον, εἴθ' ὑφιζάνοι πολεμίοις λόχον ἱππότην, τὸ ὑποδειχθησόμενον πραττέτω· οὐ μόνον δὲ τοῦτο Ἑλλήνων ἔργον καὶ εὕρεμα παλαιῶν στρατηγῶν, ἀλλὰ γὰρ καὶ Πάρθοι τοὺς ἵππους οὕτως τοὺς ἑαυτῶν ἐς τὰς μάχας ἄγουσι σιγῶντας. Νευρᾷ εὐστρόφῳ ἡ οὐρὰ τοῦ ἵππου ὑπὲρ τὴν τρίχα κατασφίγγεται, ὡς ἐνδῦναι τὸν δεσμὸν τῇ ἐπιφανείᾳ πολύν· τῇ γὰρ εὐτονίᾳ τῆς ἐπιδέσεως ὁ ἵππος ἀλγῶν, τὸν μὲν αὐτὸν θυμὸν φυλάττει καὶ τάχος, μόνον δὲ τὸ φώνημα ἴσχει, κἂν ὁ ἀναγκάζων καιρὸς ἢ ἔρως ᾖ.