As we have the authority of Thucydides for the superior repose which Attica enjoyed as compared with the rest of Greece--so (her population never having been conquered) slavery in Attica was probably of later date than elsewhere, and we may doubt whether in that favoured land the slaves were taken from any considerable part of the aboriginal race.

I say considerable part, for crime or debt would have reduced some to servitude.

The assertion of Herodotus that the Ionians were indigenous (and not conquerors as Mueller pretends), is very strongly corroborated by the absence in Attica of a class of serfs like the Penestae of Thessaly and the Helots of Laconia.

A race of conquerors would certainly have produced a class of serfs.
[65] Or else the land (properly speaking) would remain with the slaves, as it did with the Messenians an Helots--but certain proportions of the produce would be the due of the conquerors.
[66] Immigration has not hitherto been duly considered as one of the original sources of slavery.
[67] In a horde of savages never having held communication or intercourse with other tribes, there would indeed be men who, by a superiority of physical force, would obtain an ascendency over the rest; but these would not bequeath to their descendants distinct privileges.

Exactly because physical power raised the father into rank--the want of physical power would merge his children among the herd.