Aristophanes Clouds 966-68:

"Very well, I will tell you what was the old education, when I used to teach justice with so much success and when modesty was held in veneration. Firstly, it was required of a child, that it should not utter a word. In the street, when they went to the music-school, all the youths of the same district marched lightly clad and ranged in good order, even when the snow was falling in great flakes. At the master's house they had to stand with their legs apart and they were taught to sing either, "Pallas, the Terrible, who overturneth cities," or "A noise resounded from afar" in the solemn tones of the ancient harmony. If anyone indulged in buffoonery or lent his voice any of the soft inflexions, like those which to-day the disciples of Phrynis take so much pains to form, he was treated as an enemy of the Muses and belaboured with blows."