It has been already stated that, down to the time of Solon, the classification received in Attica was that of the four Ionic tribes, comprising in one scale the Phratries and Gentes, and in another scale the three Trittyes and forty-eight Naucraries—­while the Eupatridae, seemingly a few specially respected gentes, and perhaps a few distinguished families in all the gentes, had in their hands all the powers of government.  Solon introduced a new principle of classification—­called in Greek the “timocratic principle.”  He distributed all the citizens of the tribes, without any reference to their gentes or phratries, into four classes, according to the amount of their property, which he caused to be assessed and entered in a public schedule.  Those whose annual income was equal to five hundred medimni of corn (about seven hundred imperial bushels) and upward—­one medimnus being considered equivalent to one drachma in money—­he placed in the highest class; those who received between three hundred and five hundred medimni or drachmas formed the second class; and those between two hundred and three hundred, the third.  The fourth and most numerous class comprised all those who did not possess land yielding a produce equal to two hundred medimni.  The first class, called Pentacosiomedimni, were alone eligible to the archonship and to all commands:  the second were called the knights or horsemen of the state, as possessing enough to enable them to keep a horse and perform military service in that capacity:  the third class, called the [Greek:  Zeugitae], formed the heavy-armed infantry, and were bound to serve, each with his full panoply.  Each of these three classes was entered in the public schedule as possessed of a taxable capital calculated with a certain reference to his annual income, but in a proportion diminishing according to the scale of that income—­and a man paid taxes to the state according to the sum for which he stood rated in the schedule; so that this direct taxation acted really like a graduated income-tax.  The ratable property of the citizen belonging to the richest class (the Pentacosiomedimnus) was calculated and entered on the state schedule at a sum of capital equal to twelve times his annual income; that of the Hippeus, horseman or knight, at a sum equal to ten times his annual income:  that of the Zeugite, at a sum equal to five times his annual income.  Thus a Pentacosiomedimnus, whose income was exactly 500 drachmas (the minimum qualification of his class), stood rated in the schedule for a taxable property of 6,000 drachmas or one talent, being twelve times his income—­if his annual income were 1,000 drachmas, he would stand rated for 12,000 drachmas or two talents, being the same proportion of income to ratable capital.  But when we pass to the second class, horsemen or knights, the proportion of the two is changed.  The horseman possessing an income of just 300 drachmas (or 300 medimni) would stand rated for 3,000 drachmas, or ten times his real income,