The Roman Months: A Calendar Full of Gods

September through December are not named after gods at all; they are just the Latin words for seventh through tenth, fossils of a calendar that once began in March. The Roman month names are a patchwork: some genuinely religious, some disputed even among ancient scholars, and two, July and August, renamed for actual historical men rather than gods.

The old 10-month calendar and why it started in March

Roman tradition held that the earliest calendar, attributed to Romulus, had only ten months and began the year in March, the start of the campaigning and farming season. That would explain why the last four months, September through December, are simply numbered seventh through tenth from a March start, numbering that stuck even after the calendar changed and January became the formal start of the year.

Numa's addition: January and February

Roman tradition credits the legendary second king, Numa Pompilius, with adding two months, Ianuarius and Februarius, to bring the calendar to twelve months and better align it with the lunar year. Ianuarius honored Janus, the god of beginnings and transitions, an apt choice for an opening month. Februarius took its name from februa, the term for the purification rites performed during that month, rites tied to festivals like the Lupercalia. Even after Numa's reform, the pre-Julian Roman calendar remained a lunar-based system prone to drifting out of sync with the actual seasons, and the pontiffs were responsible for periodically inserting an extra intercalary month to correct it, a power they sometimes abused for political reasons, lengthening or shortening a year to extend a friendly magistrate's term or shorten a rival's.

All twelve months at a glance

Month	Latin name	Root	Confidence
January	Ianuarius	Janus	High
February	Februarius	Februa, purification rites	High
March	Martius	Mars	High
April	Aprilis	Disputed: possibly aperire, 'to open' (of buds), or linked to Aphrodite via Etruscan influence	Low / disputed
May	Maius	Disputed: the goddess Maia, or maiores, 'elders'	Disputed
June	Iunius	Disputed: the goddess Juno, or iuniores, 'the young'	Disputed
July	Iulius	Julius Caesar, renamed from Quintilis in 44 BC	High (historical event)
August	Augustus	Augustus, renamed from Sextilis in 8 BC	High (historical event)
September	September	septem, 'seven'	High
October	October	octo, 'eight'	High
November	November	novem, 'nine'	High
December	December	decem, 'ten'	High

Quintilis becomes Julius

In 44 BC, shortly after Julius Caesar's assassination, the month Quintilis, 'the fifth month,' was renamed Iulius in his honor, the name English still uses as July. The renaming also marked the broader calendar reform Caesar had enacted the previous year, the Julian calendar, which fixed the drifting Roman lunar-solar system into the roughly 365-day structure still underlying the modern calendar.

Sextilis becomes Augustus

Decades later, in 8 BC, the Roman Senate renamed Sextilis, 'the sixth month,' as Augustus, honoring the first emperor during his lifetime. Suetonius records the Senate's stated reasons connecting the month to several of Augustus's major successes. Unlike several other emperors who tried the same move, Augustus's renaming is the one that permanently stuck. The Julian reform the renaming built on, enacted by Julius Caesar in 46 BC with the help of the Alexandrian astronomer Sosigenes, fixed the year at 365 days with a leap day added every fourth year, finally ending the pontiffs' erratic intercalations and producing a calendar close enough to the modern one that most of the world still effectively uses a lightly corrected version of it today, the Gregorian calendar introduced in 1582.

Solid etymology vs. disputed months

It helps to separate months with firm ancient agreement on their god from those ancient writers themselves argued about. January, February, and March have clear, uncontested divine roots. April, May, and June are genuinely disputed: even Varro, writing with direct access to now-lost antiquarian sources, offers more than one competing explanation for some of these names rather than a single confident answer, a caution worth remembering when reading claims about the festivals Ovid describes for these same months.

Common mistakes

A frequent error is assuming September through December honor gods; they do not, they are leftover numbers from the old March-start calendar. Another is stating flatly that April is named for Aphrodite, when ancient sources themselves disagree and the 'opening buds' explanation has at least equal standing. People also sometimes assume every emperor who tried to rename a month succeeded: Caligula, Nero, Commodus, and Domitian all attempted it, and none of those renamings outlasted their reigns, unlike Caesar's and Augustus's. Caligula reportedly wanted September renamed for himself, Nero pushed to rename both April and May, Commodus briefly renamed several months after his own adopted titles, and Domitian renamed September and October after himself; in every one of these cases the Senate or the next emperor simply reverted the name once its namesake was dead or deposed, which is exactly what did not happen with Iulius and Augustus.

Why the numbered months never got renamed again

Despite several emperors' attempts, September through December kept their numerical names, perhaps because later rulers lacked Caesar's and Augustus's combination of political dominance and calendar reform to make a renaming stick, or simply because the habit of naming months after living rulers fell out of favor as the imperial cult itself grew more formalized and cautious about living honors. The Roman months, as a result, remain a genuine mix of religion, disputed etymology, and two permanent monuments to two specific men. That mix is exactly why no single clean rule, 'Roman months are named after gods' or 'Roman months are just numbers,' actually holds up; the truth, as with so much of Roman religious history, depends on checking each month individually against the ancient evidence rather than reaching for a tidy generalization. Readers curious about the specific days within each month, rather than the months themselves, will find the festival-by-festival detail in Ovid's own poetic treatment of the calendar.

Sources

• Ovid, Fasti (Books 1–6) — Poetic treatment of several month names and their associated festivals.
• Varro, De Lingua Latina (Book 6) — Antiquarian discussion and competing theories on Roman month-name etymology.
• Suetonius, Lives of the Caesars (Life of Augustus) — Records the Senate's renaming of Sextilis to Augustus and its stated reasons.

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