The term “calendar” is taken from the Latin calends or the first day of the month. It is now used to describe the division of the year ahead. The Roman calendar followed the same basic principles. But its details were somewhat different.

Months of the Roman Year

The months of the modern western calendar toughly correspond with those of the Roman calendar. The Romans originally named their months after roman gods or their numbered sequence in the calendar. Later, certain months were renamed to commemorate Roman leaders and emperors. The Roman year originally ran as follows:

• March. This was originally the first month of the year. Timed to correspond with the vernal equinox, it was named after the god Mars.
• April. Otherwise known as Aprilis, this month was associated with the goddess Venus, originally a roman garden goddess. The name may derive from the Latin “aperire”, meaning “to open”, a reference to the opening of buds or the word for “other” alius.
• May. Known as Maius, this month was named after Maia, the Roman goddess of growth.
• June. Junius in Latin, this month was sacred to Juno
• July. Originally known as Quinctilis as it was the fifth month of the Roman calendar, this month was renamed Julius after Julius Caesar’s assassination in 44BC, as he was born on its twelfth day.
• August. Originally known as Sextilis as it was the sixth month of the Roman year, this month was renamed Augustus in 8BC to commemorate the achievements of the emperor Augustus.

The next four months remained named after their original position in the Roman calendar:

• September. Known as Septem to the Romans as it was the seventh month of the year.
• October. Or Octo to reflect its original position as the roman’s eight-month
• November. Novem or the ninth month
• December. Decem — the tenth month of the Roman year. December marked the end of the Roman agricultural year.

With the end of the year in December, there was originally an uncounted gap until the vernal equinox marked the recommencement of the agricultural cycle. Legend has it that this changed during the reign of Numa Pompilius, the second King of Rome when two further months were added to the calendar to fill the vacuum of winter. They were January and February.

• January. Named after Janus, the god of gateways, thresholds, beginnings and ends, this became the first month of the roman year in 153BC to correspond with the election of consuls and magistrates to political office.
• February. Februarius was named after the festival of Februa, a purification feast held during this month.

The Roman Week

The Roman week did not follow the modern seven-day format. Instead, it was nine days long and marked out the time between market days or nundinae when agricultural produce was typically brought into the town. On the calendar for the month, the eight days between nundinae were marked by the letters A-H with the market day assigned no letter at all. The day after the market, the cycle began again. The uneven numbers involved meant that the roman days of the week varied from month to month and year to year.

Lucky and Unlucky Roman Dates

On the first day of the month, a herald would announce all the festivals for the month ahead, including the days on which business could or could not be transacted. These days were listed as dies fasti, dies nefasti, dies comitiales, endotercisus and dies nefasti publici and were marked by different letters on the public calendars.

• Dies fasti. Represented by the letter F, this was a day when it was acceptable for legal action or business to be undertaken.
• Dies nefasti. Represented by the letter N, this was an unlucky day for legal and political action.
• Dies comitiales. Represented by a C, these were days when the citizen assemblies, the comitia, could vote.
• Endotercisus was a divided day. Represented by EN on the calendar, it represented a day when religious activities occupied the first and last portion of the day whilst the period between remained acceptable for business. Typically, in the morning, an animal would be sacrificed and burnt its entrails read in the evening. During both these periods, it was unlucky or nefasti to conduct business. But the period in-between the two ceremonies was dies fasti.
• Dies nefasti publici. Marked as NP on the calendar, this marked specific special days, such as New Year’s Day or the ides of the month, which were deemed unlucky for public and private business.

Resources.

Boyle, A J and Woodard, R D (trans and edited) (2000) Ovid’s Fasti. Penguin Books: London.

The Oxford Classical Dictionary.

Chambers Book of Days (2004). Chambers Harrap Publishers: Edinburgh.