Αποστολος, (_Apostolos_) is derived from the preceding verb by changing the penult vowel Ε into Ο, and displacing the termination of the verb by that of the noun. The change of the penult vowel is described in the grammars as caused by its being derived from the perfect middle, which has this peculiarity in its penult. The noun preserves in all its uses the uniform sense of the verb from which it is derived, and in every instance maintains the primary idea of “a person or thing _sent_.” It was often used adjectively with a termination varying according to the gender of the substantive to which it referred. In this way it seems to have been used by Herodotus, who gives it the termination corresponding to the neuter, when the substantive to which it refers is in that gender. (See Porti Dictionarium Ionicum Græco Latinum.) Herodotus is the earliest author in whom I am able to discover the word, for Homer never uses the word at all, nor does any author, as far as I know, previous to the father of history. Though always preserving the primary idea of the word, he varies its meaning considerably, according as he applies it to a person or a thing. With the neuter termination αποστολον, (_apostolo_N,) referring to the substantive πλοιον, (_ploion_,) it means a “vessel _sent_” from place to place. In Plato, (Epistle 7,) it occurs in this connection with the substantive πλοιον expressed, which in Herodotus is only implied. For an exposition of this use of the term, see H. Stephens’s Thesaurus, (sub voc. αποστολος.) With the masculine termination, Herodotus, applying it to persons, uses it first in the sense of “messenger,” “embassador,” or “herald,” in Clio, 21, where relating that Halyattes, king of Lydia, sent a herald (κηρυξ,) to treat for a truce with the Milesians, he mentions his arrival under this synonymous term. “So the messenger (αποστολος, _apostolos_,) came to Miletus.” (Ὁ μεν δη αποστολος ες την Μιλητον ἦν.) In Terpsichore, 38, he uses the same term. “Aristagoras the Milesian went to Lacedæmon by ship, as _embassador_ (or delegate) from the assembly of Ionic tyrants,” (Αποστολος εγινετο.) These two passages are the earliest Greek in which I can find this word, and it is worth noticing here, that the word in the masculine form was distinctly applied to persons, in the sense given as the primary one in the text of this book. But, still maintaining in its uses the general idea of “sent,” it was not confined, in the ever-changing usage of the flexible Greeks, to individual persons alone. In reference to its expression of the idea of “distant destination,” it was applied by later writers to naval expeditions, and in the speeches of Demosthenes, who frequently uses the word, it is entirely confined to the meaning of a “warlike expedition, _fitted out_ and _sent_ by sea to a distant contest.”