20. Trusting my reader then in future to retain in his mind without confusion the idea of the three zones, Gothic, Classic, and Arab, each divided into four countries, clearly recognizable through all ages of remote or recent history;--I must farther, at once, simplify for him the idea of the Roman _Empire_ (see note to last paragraph,) in the manner of its affecting them. Its nominal extent, temporary conquests, civil dissensions, or internal vices, are scarcely of any historical moment at all; the real Empire is effectual only as an exponent of just law, military order, and mechanical art, to untrained races, and as a translation of Greek thought into less diffused and more tenable scheme for them. The Classic zone, from the beginning to the end of its visible authority, is composed of these two elements--Greek imagination, with Roman order: and the divisions or dislocations of the third and fourth century are merely the natural apparitions of their differences, when the political system which concealed them was tested by Christianity. It seems almost wholly lost sight of by ordinary historians, that, in the wars of the last Romans with the Goths, the great Gothic captains were all Christians; and that the vigorous and naive form which the dawning faith took in their minds is a more important subject of investigation, by far, than the inevitable wars which followed the retirement of Diocletian, or the confused schisms and crimes of the lascivious court of Constantine. I am compelled, however, to notice the terms in which the last arbitrary dissolutions of the empire took place, that they may illustrate, instead of confusing, the arrangement of the nations which I would fasten in your memory.