Romulus
The legendary founder and first king of Rome, son of Mars, to whom Roman writers gave the first calendar of ten months beginning in March.
legendary
How the Romans fixed the year
Censorinus, On the Birthday 20–22 (238 CE), in the edition of Friedrich Hultsch (Leipzig, 1867) · 238 CE
Nomina decem mensibus antiquis Romulum fecisse Fulvius et Iunius auctores sunt. et quidem duos primos a parentibus suis nominasse, Martium a Marte patre, Aprilem ab Aphrodite, id est Venere, unde maiores eius oriundi dicebantur. proximos duos a populo, Maium a maioribus natu, Iunium a iunioribus. ceteros ab ordine quo singuli erant, Quintilem usque Decembrem perinde a numero.
Fulvius and Junius report that Romulus named the ten ancient months. He named the first two after his parents: March (Martius) after his father, Mars, and April (Aprilis) after Aphrodite, that is, Venus, from whom his ancestors were said to descend. He named the next two after the people: May (Maius) after the elders (maiores), and June (Iunius) after the younger men (iuniores). The rest, from Quintilis to December, he named by their place in order, by number.
itaque Martium mensem a Marte quidem nominatum credit, non quia Romuli fuerit pater, sed quod gens Latina bellicosa. Aprilem autem non ab Aphrodite, sed ab aperiendo, quod tunc ferme cuncta gignantur et nascendi claustra aperiat natura.
So he believes that March was indeed named after Mars, but not because Mars was the father of Romulus. It was because the Latin people were warlike. April, he thinks, came not from Aphrodite but from "opening" (aperire), because almost everything is born then, and nature opens the gates of birth.
Where the months got their names
Macrobius, Saturnalia 1.12–14 (early fifth century CE), in the edition of Franz Eyssenhardt (Leipzig, 1893) · early fifth century CE; the dialogue is set in the 380s
non igitur mirum in hac uarietate Romanos quoque olim auctore Romulo annum suum decem habuisse mensibus ordinatum, qui annus incipiebat a Martio, et conficiebatur diebus trecentis quattuor, ut sex quidem menses, id est Aprilis Iunius Sextilis September Nouember December, tricenum essent dierum, quattuor uero, Martius Maius Quintilis October, tricenis et singulis expedirentur, qui hodieque septimanas habent Nonas, ceteri quintanas.
So with all this variety it is no surprise that the Romans too once had a year of ten months, set up by Romulus. This year began with March and was 304 days long. Six months, April, June, Sextilis, September, November and December, had 30 days each. The other four, March, May, Quintilis and October, had 31 days each. These four still have their Nones on the seventh day; the rest have them on the fifth.
Haec fuit Romuli ordinatio, qui primum anni mensem genitori suo Marti dicauit. quem mensem anni primum fuisse uel ex hoc maxime probatur, quod ab ipso Quintilis quintus est, et deinceps pro numero nominabantur.
This was Romulus's plan. He dedicated the first month of the year to his father, Mars. The clearest proof that March was the first month is that Quintilis is the fifth month counting from it, and the months after it were named by their numbers.
Secundum mensem nominauit Aprilem, ut quidam putant cum adspiratione quasi Aphrilem, a spuma quam Graeci ἀφρὸν uocant, unde orta Venus creditur, et hanc Romuli asserunt fuisse rationem, ut primum quidem mensem a patre suo Marte, secundum ab Aeneae matre Venere nominaret, et hi potissimum anni principia seruarent, a quibus esset Romani nominis origo, cum hodieque in sacris Martem patrem, Venerem genetricem uocemus.
He named the second month Aprilis. Some think the name was first said with an h, as Aphrilis, from the sea foam that the Greeks call aphros, from which Venus is believed to have been born. They claim that this was Romulus's reasoning. He named the first month after his father, Mars, and the second after Venus, mother of Aeneas. He wanted the gods from whom the Roman people came to hold the start of the year above all. Even today, in our rites, we call Mars "Father" and Venus "Mother."
alii putant Romulum uel altiore prudentia uel certi numinis prouidentia ita primos ordinasse menses ut, cum praecedens Marti esset dicatus deo plerumque hominum necatori, ut Homerus naturae conscius ait Ἆρες Ἄρες βροτολοιγὲ μιαιφόνε τειχεσιβλῆτα secundus Veneri dicaretur, quae uim eius quasi benefica leniret.
Others think that Romulus, through deeper wisdom or the guidance of some god, arranged the first months so that one would balance the other. The first was dedicated to Mars, a god who most often brings death to men. As Homer, who understood his nature, says, "Ares, Ares, ruin of men, stained with blood, stormer of walls!" So the second was dedicated to Venus, whose kindness might soften his violence.
Maium Romulus tertium posuit. de cuius nomine inter auctores lata dissensio est. nam Fulvius Nobilior in fastis, quos in aede Herculis Musarum posuit, Romulum dicit, postquam populum in maiores iunioresque diuisit, ut altera pars consilio, altera armis rem publicam tueretur, in honorem utriusque partis hunc Maium, sequentem Iunium mensem uocasse.
Romulus put May third. Writers disagree widely about its name. Fulvius Nobilior wrote about it in the calendar he set up in the temple of Hercules of the Muses. He says that Romulus divided the people into the elders (maiores) and the younger men (iuniores). One group was to guard the state with counsel and the other with arms. In honor of each group Romulus called this month Maius and the next Iunius.
Sequitur Iulius qui, cum secundum Romuli ordinationem, Martio anni tenente principium, Quintilis a numero uocaretur, nihilo minus tamen etiam post praepositos a Numa Ianuarium ac Februarium retinuit nomen, cum non uideretur iam quintus esse sed septimus. sed postea in honorem Iulii Caesaris dictatoris, legem ferente M. Antonio M. filio consule, Iulius appellatus est, quod hoc mense a. d. quartum Idus Quintilis Iulius procreatus sit.
Next comes July. Under Romulus's plan, when March began the year, it was called Quintilis from its number, "fifth." It kept that name even after Numa put January and February in front of it, though it no longer seemed to be the fifth month but the seventh. But later it was named Iulius in honor of Julius Caesar the dictator, under a law proposed by the consul Mark Antony, son of Marcus. The reason was that Julius had been born in this month, on the fourth day before the Ides of Quintilis.
Haec fuit a Romulo annua ordinata dimensio qui, sicut iam supra diximus, annum decem mensium, dierum uero quattuor et trecentorum habendum esse constituit, mensesque ita disposuit, ut quattuor ex his tricenos singulos, sex uero tricenos haberent dies.
This was the measure of the year that Romulus set up. As I said before, he decided that the year should have ten months and 304 days. He arranged the months so that four of them had 31 days and six had 30.