The men from twenty-six to fifty occupy the third, and the elders the fourth, quarter of the Agora. The former act as a standing army of heavy infantry; the latter as a reserve force for home defence, as Judges, as the electors to the offices of State, and as the teachers of the children. The other offices are filled by the third age. Any freeborn Persian can climb this four-runged Ladder of Education to the very top; but no one may enter a higher class without having served his full time in those below it. To Xenophon, it appears, belongs the credit of being the first theorist to recognise the merits of this Thessalian custom of the “Free Agora,” the State-provided centre of culture, afterwards adopted so extensively in Alexandria, where the educated classes of all ages might meet in an intellectual atmosphere and amid beautiful surroundings, and provide that exchange and mart of ideas by personal intercourse which Newman considered to be the essence of a University. In the Free Agora of Utopian Persia all the educated spend their days, influencing one another by talk and example, exchanging and criticising ideas, competing in warlike exercises――and all in an atmosphere untainted by the vulgarity of money-making. On the other hand, culture there does not mean idleness; to Xenophon, as to Plato, education seemed to entail great responsibilities, and the educated classes provide the sole standing army of the State and have to give their countrymen the benefit of their intelligence by serving as Rulers and Judges.