History of the Peloponnesian War

The Thracians, then, having burst into Mycalessus, plundered both private houses and temples, and butchered the inhabitants, sparing neither old age nor youth, but killing one after another all they met with, both children and women, nay, further, even cattle and beasts of burden, and whatever other living things they saw. For the Thracian race, like the most blood-thirsty of the barbarians, is most so when secure from resistance. And thus on that occasion there was no little confusion in other respects, and every form of butchery was exhibited.

And, in particular, they attacked a boys' school, the largest there was in the place, (which the children had just entered,) and cut them all to pieces. And this disaster, which fell on the whole town, was inferior to none in extent, while it was more unexpected and shocking than any other.