The headmaster of the school sat on a chair with a high back; under-masters and boys had stools without backs, but cushions were provided. For lessons in class there were benches.[224] There was a high reading-desk for recitations. Round the walls hung writing-tablets, rulers, and baskets or cases containing manuscript rolls labelled with the author’s name, composing the school library; the rolls might also hang by themselves.[225] Masters were expected to possess at any rate a copy of Homer――Alkibiades thrashed one who did not. Sometimes they emended their edition themselves.[226] In the music-schools hung lyres and flutes and flute-cases. The παιδαγωγειον [paidagôgeion] mentioned by Demosthenes may have been an anteroom where the paidagogoi sat, but more probably the word is only a rhetorical variant for “schoolroom.” There were often busts of the Muses round the walls,[227] which were also decorated with vases, serving for domestic purposes, and, perhaps, illustrating with their pictures the books which the boys were reading. At a later date, at any rate, a series of cartoons, illustrating scenes in the _Iliad_ and _Odyssey_, were sometimes hung upon the walls: the “Tabula Iliaca,” now in the Capitoline Museum, has been recognised as a fragment of such a series. The first stage was to learn to read and write. Instead of a slate, boys in Hellas had tablets of wax, usually made in two halves, so as to fold on a hinge in the middle, the waxen surfaces coming inwards and so being protected. Sometimes there were three pieces, forming a triptych, or even more. For pencil, they had an instrument with a sharp point at one end, suitable for making marks on the wax, and a flat surface at the other, which was used to erase what had been written, and so make the tablets ready for future use. These tablets are shown in the school-scenes on the fifth-century vases.[228] At a later period, when parchment and papyrus became more common, these materials were used in the schools. Lines could be ruled with a lump of lead, and writing done either with ink and a reed pen or with lead; for erasures a sponge was employed.