Fifth century Greece, convulsed by the Peloponesian war, contained terrible acts of violence. You would have thought that in the end people would have got so inured to this violence and that nothing could shock them. However even Thucydides who can be quite detached was shocked by the incident below. The background was that the Athenians had hired some Thracian mercenaries but realising that they would not have the money to pay them sent them back to Thrace. On the way back by ship, they stopped off in Boeotia and this is what happened.
ἐσπεσόντες δὲ οἱ Θρᾷκες ἐς τὴν Μυκαλησσὸν τάς τε οἰκίας καὶ τὰ ἱερὰ ἐπόρθουν καὶ τοὺς ἀνθρώπους ἐφόνευον φειδόμενοι οὔτε πρεσβυτέρας οὔτε νεωτέρας ἡλικίας, ἀλλὰ πάντας ἑξῆς, ὅτῳ ἐντύχοιεν, καὶ παῖδας καὶ γυναῖκας κτείνοντες, καὶ προσέτι καὶ ὑποζύγια καὶ ὅσα ἄλλα ἔμψυχα ἴδοιεν: τὸ γὰρ γένος τὸ τῶν Θρᾳκῶν ὁμοῖα τοῖς μάλιστα τοῦ βαρβαρικοῦ, ἐν ᾧ ἂν θαρσήσῃ, φονικώτατόν ἐστιν. καὶ τότε ἄλλη τε ταραχὴ οὐκ ὀλίγη καὶ ἰδέα πᾶσα καθειστήκει ὀλέθρου, καὶ ἐπιπεσόντες διδασκαλείῳ παίδων, ὅπερ μέγιστον ἦν αὐτόθι καὶ ἄρτι ἔτυχον οἱ παῖδες ἐσεληλυθότες, κατέκοψαν πάντας: καὶ ξυμφορὰ τῇ πόλει πάσῃ οὐδεμιᾶς ἥσσων μᾶλλον ἑτέρας ἀδόκητός τε ἐπέπεσεν αὕτη καὶ δεινή.
τῶν δὲ Μυκαλησσίων μέρος τι ἀπανηλώθη. τὰ μὲν κατὰ τὴν Μυκαλησσὸν πάθει χρησαμένην οὐδενὸς ὡς ἐπὶ μεγέθει τῶν κατὰ τὸν πόλεμον ἧσσον ὀλοφύρασθαι ἀξίῳ τοιαῦτα ξυνέβη.
The Thebans fell on Mykalessus and sacked their houses and temples, sparing neither young or old but killing anyone they met including women and children and even the beasts of burden and any other living thing they saw. For the Thracian race, like the most extreme barbarian race, is most bloodthirsty when it has has its courage up and in this case apart from the rest of the turmoil and slaughter, they fell upon a school of children, which was the largest there and where the children had just gone in, and they cut them all down. That disaster, second to none, came upon the whole city more unexpected and terrible than any other.
The greater part of the Mykelessians were destroyed. This is what happened at Mykelessus which suffered a tragedy more heartrending than anything else in the war when you take into account the size of the city.