This system of primary education at Athens may reasonably be traced back to the beginning of the sixth century. Solon is credited with a regulation which made letters compulsory, and with certain moral enactments dealing with existing schools and palaistrai. The much-disputed popularisation of Homer at Athens by Peisistratos was probably connected with the growth of the Schools of Letters. Of the existence of music-schools at this date there is evidence from a sixth-century vase in the British Museum,[131] which represents a youth amusing himself with a dog, behind a seated man who is playing a lyre. This might not seem very conclusive in itself; but now compare it with the two “amphorai” of the fifth century,[132] which undoubtedly represent scenes in a music-school. The situation is almost identical; each alike shows the boy playing with the animal behind his master’s chair. Curiously enough, all three vases come from Kameiros in Rhodes, although they are of Athenian manufacture. Thus the music-school may also be traced back well into the sixth century, in company with the school of letters and the palaistra; and the antiquity of the system of Primary Education is thus established. [Illustration: PLATE I. A. THE FLUTE LESSON, THE WRITING LESSON (ABOVE A WRITING-ROLL, A FOLDED TABLET, A RULING SQUARE, ETC.) From the Kulix of Douris, now at Berlin (No. 2285). _Monumenti dell’ Instituto_, ix. Plate 54.] [Illustration: PLATE I. B. THE LYRE LESSON, AND THE POETRY LESSON (ABOVE IS AN ORNAMENTAL MANUSCRIPT BASKET) From a Kulix by Douris, now in Berlin (No. 2285). _Monumenti dell’ Instituto_, ix. Plate 54.] In earlier days this primary course had no doubt sometimes lasted till the boy was eighteen: but towards the end of the fifth century a secondary stage of education arose, occupying the years immediately preceding eighteen. This secondary stage is recognised in the pseudo-Platonic _Axiochos_ and in the fragment of Teles quoted by Stobaeus. More important evidence is supplied by Plato. In the _Republic_ he assigns an elaborate system of mathematics to the age just before ἐφηβεία [ephêbeia], which he sets at seventeen or eighteen, the natural age varying with the individual, while the legal age remained fixed.