Etymologiae, Book I, chapters 38-39: De prosa to De metris
Chapter XXXVIII. On prose Prose is speech extended and loosed from the law of metre. For the ancients called prosum what is extended and straight. Hence Varro says that in Plautus prosis lectis means “straight”; whence also speech that is not bent by number but is straight is called prose, by being drawn out straight. Others say prose is so called because it is poured forth (profusa), or because it rushes and runs on more spaciously, with no limit fixed for itself. Moreover, among the Greeks as among the Latins, care for verses was far older than for prose. For everything was at first composed in verse; the study of prose flourished late. Among the Greeks the first to write in loose speech was Pherecydes of Syros; among the Romans Appius Caecus first practised loose speech, against Pyrrhus. From then on others too strove for eloquence in prose.
Chapter XXXIX. On metres Metres are so called because they are bounded by fixed measures and spaces of feet and do not go beyond the established dimension of times. For measure is called metron in Greek. Verses (versus) are so called because, with the feet arranged in their order, they are regulated to a fixed end through joints, which are called caesuras and members. Lest they be rolled on farther than judgment could bear, reason set a limit from which they should turn back; and the verse itself was named from the fact that it turns back (revertitur). Closely related is rhythm, which is not regulated by a fixed end, but runs with feet reasonably ordered; in Latin it is called nothing other than number, of which is that line: “I remember the numbers, if I held the words.” A song (carmen) is called whatever is contained in feet: the name is thought to have been given either because it is pronounced in pieces (carptim), whence today we say carminare of wool which cleansers tear apart; or because those who sang them were thought to be lacking (carere) in mind. Metres are named either from the feet, or from the matters written, or from the inventors, or from those who used them often, or from the number of syllables. From the feet metres are named, as dactylic, iambic, trochaic. For the trochaic metre is born of the trochee, the dactylic of the dactyl; so also the others from their own feet. From number, as hexameter, pentameter, trimeter. For we call verses of six feet senarii from the number of feet. The Greeks call these trimeters, because they strike twin feet. Ennius is reported to have been the first to make hexameters among the Latins; and they call them “long.” From inventors metres are said to be named, as Anacreontic, Sapphic, Archilochian. For Anacreon composed the Anacreontic metres; the woman Sappho brought out the Sapphic; a certain Archilochus wrote the Archilochian; a certain man of Colophon practised the Colophonian. The inventor of the Sotadean also is Sotades, a Cretan by race. The Simonidean metres were also composed by Simonides the lyric poet. From those who used them often, as the Asclepiad. For Asclepius did not invent them, but they were so called because he used them most elegantly and most frequently. From the matters written, as heroic, elegiac, bucolic. The heroic song is so called because in it the deeds and acts of brave men are narrated. For heroes are men so called as if airy (aerii) and worthy of heaven on account of wisdom and fortitude. This metre precedes the other metres in authority; alone of all it is fitted to the greatest works as to small, equally capable of sweetness and charm. By these virtues it alone obtained the name, being called heroic, namely to commemorate their deeds. For it is also held the simplest of all and consists of two feet, the dactyl and the spondee, and often almost of either this or that; save that it becomes most temperate by the mixture of both rather than if it were furnished from single feet. It is also prior to all metres. Moses is proved to have sung this first in the canticle of Deuteronomy, long before Pherecydes and Homer. Whence it appears that the study of songs among the Hebrews was older than among the Gentiles, since Job also, a contemporary of Moses, runs on in hexameter verse, with dactyl and spondee. Among the Greeks Achatesius of Miletus is said to have composed it first, or, as others think, Pherecydes of Syros. This metre before Homer was called Pythian, after Homer heroic. They wish it called Pythian because the oracles of Apollo were delivered in this kind of metre. For when on Parnassus he pursued the serpent Python with arrows to avenge his mother, the neighbouring people of Delphi encouraged him in this metre, saying, as Terentianus says: “Hie paian, hie paian, hie paian.”
The elegiac is so called because the modulation of that song suits the wretched. Terentianus is wont to call these elegi, because such a close, as they say, is better suited to sad measures. By whom it was invented is hardly settled at all, except that among us Ennius used it first. For among the Greeks the dispute of the grammarians so hangs that the matter is left to a judge. For some wish a certain man of Colophon, some Archilochus, to be the author and inventor. The bucolic, that is, pastoral song, most think was first composed by shepherds at Syracuse, some at Lacedaemon. For when Xerxes, king of the Persians, was crossing into Thrace, and the Spartan maidens, under fear of the enemy, could neither go out of the city nor perform the rustic procession and chorus of Diana according to custom, a crowd of shepherds, lest the rite be omitted, celebrated it with unpolished songs. It is called bucolic from the greater part, although the speeches and songs of sheep-keepers and goatherds are inserted in them. It is clear that the prophet David first composed and sang hymns in praise of God. Then among the Gentiles Memmia Timothoe first made them to Apollo and the Muses, who lived in the times of Ennius, long after David. Hymns are interpreted from Greek into Latin as praises. Epithalamia are the songs of those marrying, which are sung by the scholars in honour of the bridegroom and the bride. Solomon first brought these out in praise of the Church and of Christ. From that time the Gentiles claimed the epithalamium for themselves, and a song of this kind was adopted. This kind was first celebrated by the Gentiles on the stage, and afterwards clung only to weddings. It is called epithalamium because it is sung in the bridal chambers (thalami). Threnodies, which in Latin we call lament, Jeremias first composed in verse over the city of Jerusalem when it was overthrown, and over the people of Israel when they were overthrown and led captive. After him among the Greeks the lyric poet Simonides. They were used at funerals and lamentations: likewise now. Epitaph in Greek, in Latin “upon the tomb.” It is the inscription of the dead, which is made at the sleep of those who are already departed. For there their life, manners and age are written. Poesis is called by a Greek name the work of many books, poem that of one, idyll of few verses, distich of two, monostich of one. An epigram is an inscription, which in Latin is interpreted as superscription; for epi means upon, and gramma letter or writing. The epode in a poem is a short close. It is called epode because it is sung as an addition to the form of the elegiac, where, one longer verse being put first, a shorter is composed, and after each of the longer ones the following shorter ones sing back, as closes. The lyric poets call closes, as it were, curtailed verses subjoined to entire ones, as in Horace (Epod. 2, 1): “Happy he who far from business,” then follows the curtailed one: “As the ancient race of mortals”; so also thereafter alternately, those lacking some part, like the preceding but shorter. Centos are commonly so called among the grammarians, who from the songs of Homer or Virgil, in the manner of a patchwork (cento), stitch into one body, from many pieces put together from here and there, works of their own, according to the capacity of each subject. Finally, Proba, wife of Adelphus, expressed most fully a cento from Virgil on the Fabric of the world and on the Gospels, the material being composed according to the verses and the verses fitted according to the material. So also a certain Pomponius from the same poet, among the other leisures of his pen, composed a Tityrus in honour of Christ; likewise also from the Aeneid.