There is speculation that prior to the republic Roman calendar there was an earlier calendar instated by Romulus and consisting of ten months. I do not want to discuss here whether Romulus existed and whether, if he did exist, set up the calendar. I want to understand whether the calendar itself existed.

Over the years, I have seen sources claiming it as a fact that there was a pre-republican calendar from March to December and other sources claiming that there is no real evidence in its support. So, what written evidence is there in support of the alleged existence of a ten-month calendar starting in March? The text can be fragmentary old calendars, mentions in other literature, or something else. I would like to exclude the numbering of the names of the months Quintilis through December as indirect evidence and focus on remains or mentions of actual calendars.


1 Answer 1


The WP article on the Roman Calendar, section Republican Calendar, apparently synthesizes all what is known.

  • Unfortunately, the strongest evidence for a 10-month calendar seems to be what you have excluded, i.e., the names of the months Quntilis (July) through December.
  • The first known attestation that there was a 10-month calendar prior to the Republican Calendar, and created by Romulus, seems to date to c. 400 AD:

    Non igitur mirum in hac varietate Romanos quoque olim auctore Romulo annum suum decem habuisse mensibus ordinatum, qui annus incipiebat a Martio et conficiebatur diebus trecentis quattuor (Macrobius, Saturnalia 1.XII.3,)

    which is kind of frustrating, since it doesn't sound very trustworthy (the Saturnalia itself is written in the form of dialogues, and mixes mythology with history, making difficult to tell what to believe). Modern scholars disagree on whether to give credit to this evidence or not.

  • A number of authors from the I Century BC and the I Century AD offer contradicting versions about the origin of January and February as the first two months of the year, dating it from as early as the VI to as late as the II Century BC. At least one XX-Century author believes these were still the last two months of the year for priests during the Republic. They seem to agree that before this change there was a 12-month calendar with March as the fisrt month.

  • Theodor Mommsen (1864), History of Rome, p.214, argues that the decimal was the preferred system among Indo/Germanic peoples in general and the Italic in particular, and cites the 10-month calendar (which he assumes true) as an example:

    (...) In the case of Italy the decimal system pervaded the earliest arrangements: it may be sufficient to mention the occurrence of the number ten so commonly in the case of witnesses, securities, ambassadors, and magistrates, the legal equivalence of one ox and ten sheep, the partition of canton into ten curies and the pervading application generally of the decurial system, the limitatio, the tenth in offerings and in agriculture, decimation, and the praenomen Decimus. Among the applications of this most ancient decimal system in the sphere of measuring and of writing, the remarkable Italian ciphers claim a primary place. When the Greeks and Italians separated, there were still, evidently, no conventional signs of number. On the other hand, we find the three oldest and most indispensable numerals, one, five, and ten, represented by three signs—I, V or Λ, X, manifestly imitations of the outstretched finger, and the open hand single and double—which have not been derived either from the Hellenes or the Phoenicians, but are common to the Romans, Sabellians, and Etruscans. They are the first steps towards the formation of a national Italian writing, and at the same time evidences of the liveliness of that earlier inland intercourse among the Italians which preceded their transmarine commerce (P. 203). Which of the Italian stocks invented, and which of them borrowed these signs, can of course no longer be ascertained. Other traces of the pure decimal system occur but sparingly in this field; among them are the vorsus, the Sabellian measure of surface of 100 square feet (P. 22), and the Roman year of ten months.

  • Anyway, among those who favor the hypothesis of a 10-month year, some argue that there were a number of additional days belonging to no month in particular, or that there were two or three additional intercalary months (note that it is common among lunisolar calendars to have leap months instead of leap days).

  • I wrap my head around this possibility by imagining that the early Romans felt no need for a year divided in months. If the months were needed to mark agriculturally important times, as in some cultures today, the winter months might have been unnecessary to demark with any special names. You then could have priests deciding when to prepare for the new year in February during the count down to the first new moon or Kalendae of spring in March. Commented Feb 3, 2022 at 21:58
  • As you come into contact with cultures that are more astronomically oriented, you might want to start counting down by using months dated from some time near the solstice, i.e., January, and show off your new scientific sophistication. Commented Feb 3, 2022 at 22:00

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