It was on the occasion of this tax that they introduced a great change in the financial arrangements and constitution of the city; a change conferring note upon the archonship of Nausinikus, (B.C. 378-377). The great body of substantial Athenian citizens as well as metics were now classified anew for purposes of taxation. It will be remembered that even from the time of Solon[235] the citizens of Athens had been distributed into four classes,—Pentakosiomedimni, Hippeis, Zeugitæ, Thêtes,—distinguished from each other by the amount of their respective properties. Of these Solonian classes, the fourth, or poorest, paid no direct taxes; while the three former were taxed according to assessments representing a certain proportion of their actual property. The taxable property of the richest (or Pentakosiomedimni, including all at or above the minimum income of five hundred medimni of corn per annum) was entered in the tax-book at a sum equal to twelve times their income; that of the Hippeis (comprising all who possessed between three hundred and five hundred medimni of annual income) at ten times their income; that of the Zeugitæ (or possessors of an annual income between two hundred and three hundred medimni) at five times their income. A medimnus of corn was counted as equivalent to a drachma; which permitted the application of this same class-system to movable property as well as to land. So that, when an actual property-tax (or _eisphora_) was imposed, it operated as an equal or proportional tax, so far as regarded all the members of the same class; but as a graduated or progressive tax, upon all the members of the richer class as compared with those of the poorer. [235] For the description of the Solonian census, see Vol. III, Ch. xi, p. 117, of this History.