prThose, O Emperor, who at great length have explained their inventions and doctrines, have thereby given to their writings an extended and singular reputation. Would that such were the case with my labours, so that amplification might bring reputation with it. That, however, I believe is not probable, since a treatise on Architecture is not like History or Poetry. History interests the reader by the various novelties which occur in it; Poetry, on the other hand, by its metre, the feet of its verses, the elegant arrangement of the words, the dialogue introduced into it, and the distinct pronunciation of the lines, delighting the sense of the hearer, leads him to the close of the subject without fatigue.
2This cannot be accomplished in Architectural works, because the terms, which are unavoidably technical, necessarily throw an obscurity over the subject. These terms, moreover, are not of themselves intelligible, nor in common use; hence if the precepts which are delivered by authors extend to any length, and are otherwise explained than in few and perspicuous expressions, the mind of the reader is bewildered by the quantity and frequent recurrence of them. These reasons induce me to be brief in the explanation of unknown terms, and of the symmetry of the parts of a work, because the matter may thereby be more easily committed to and retained by the memory.
3I am moreover inclined to be concise when I reflect on the constant occupation of the citizens in public and private affairs, so that in their few leisure moments they may read and understand as much as possible. Pythagoras and his followers wrote the precepts of their doctrines in cubical arrangement, the cube containing two hundred and sixteen verses, of which they thought that not more than three should be allotted to any one precept.
4A cube is a solid, with six equal square faces, which, however it falls, remains steady and immoveable till removed by force: such are the dice which are thrown on a table by gamesters. From this circumstance they seem to have adopted the cube, since like the cube, this number of verses makes a more lasting impression on the memory. The Greek comic poets have also divided the action of their stories, by the interposition of the chorus to ease the principal actors, so that a cubical proportion is observed.
5Since the ancients therefore used these methods, founded on the observance of natural effects, seeing that the subject I treat of will be new and obscure to many, I thought it would be preferable to divide it into small portions, that it might more easily strike the understanding of the reader. The subjects also are so arranged, that those of the same nature are classed together. Thus, O Cæsar, I explained the proportions of temples in the third and fourth books; in this I intend to describe the arrangement of public buildings; and that of the forum first, because therein public no less than private affairs are regulated by the magistrates.