The Roman Calendar Reading - Medina City Schools

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The Romans displayed an ability to borrow ideas from other cultures, often improving them in many ways.
While the same can be said about the system of Roman dating, the calculation of Roman dates and days of the
week is a rather laborious task.
From our modern perspective, the system is filled with rules and oddities that seem unnecessarily difficult.
Nonetheless, by learning some rules we can successfully master the Roman system of calculating dates.
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In modern day books, one will find the terms B.C. (Before Christ) and A.D. (Anno Domini, “in the year of the
lord”) to calculate dates. 1
This system of dating, however, would have meant nothing to the Romans. They calculated years in one of two
ways:
1.) By counting backwards from the year 753 B.C., the year in which Rome was founded. 2 The Latin
phrase used when providing a date in this manner was, Ab Urbe Condita (A.U.C), “from the
city having been founded.”). The Romans would provide a year by saying how many years had elapsed since the
founding of Rome. For example, the year 59 B.C. could have been expressed by the Romans as 694 A.U.C.
(i.e. 694 years after the year 753 B.C.).
2.) By naming the consuls for the year to which they are referring. The consuls were the chief officials
in a given year during the Roman republic. Roman historians often indicating a year by naming the two
consuls for that year. For example, the year 59 B.C. could have also been expressed by the Romans as
C. Iulio Caesare et M. Calpurnio Bibulo Consulibus, “In the consulship of Gaius Juilius Caesar and Marcus
Calpurnius Bibulus.”
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The Roman calendar originally consisted of 10 months, with the year starting in March. Tradition holds that
Numa Pompilius, the second king of Rome later added the months of January and February.
In the beginning, the Romans originally used a solar calendar, which resulted in a year of 355 days. This meant
that the Roman calendar was out of sync with the solar year by 10 days, and it was the job of the ponitfex
maximus to sometimes insert an extra month to bring the calendar in line with the actual solar year.
By the time of Julius Caesar, the calendar was off by several months. In his role as pontifex maximus in 46 B.C.,
Caesar (who became aware of the solar year while in Egypt) converted the Roman calendar to the solar year,
resulting in a day of 365 years. This calendar was remarkably accurate, not requiring any correction until the
Gregorian calendar was implemented by Pope Gregory XIII in 1582 A.D..
The name of the month Quintilis (“Fifth”) was changed to “Julius” (July) in honor of Julius Caeasar; later the
month of Sextilis (“Sixth”) was changed to “Augustus” (August) to honor Caesar Augustus.
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A Roman day consisted of 24 hours, but they were not calculated the same way which they are today. The
Romans divided each day into two parts: 12 hours of daytime and 12 hours of nightime. The Romans,
however, measured hours from dawn till dusk and from dusk till dawn and so the length of an hour changed
according to the time of year (for example, hourse were longer during summer).
The first two hours of a Roman’s morning were given to the salutatio: the time when a patron approached a
client to receive (1) any instructions for work that needed to be done (2) the sportula: their provisions of of
food (or money for food).
The Romans originally did not have a 7 day week (this was not adpoted by the Romans until 321 A.D. The
Romans named each day after one of the visible planets associated with the gods: Dies Lunae (Monday), Dies
1 This system is now being phased out by many in favor of the more “politically correct” terms, “B.C.E.” (Before Common
Era) and “C.E.” (Common Era).
2 This date was decided rather arbitrarily in the 1st century B.C. by the Roman writer Varro. Modern archaeology,
however, has found it to be rather accurate.

Martis (Tuesday), Dies Mercurius (Wednesday), Dies Iovis (Thursday), Dies Veneris (Friday), Dies Saturni
(Saturday), and Dies Solis (Sunday).
The Roman calendar, however, was divided into eight day periods known as nundina. Every eighth day of the
Roman calendar was known as a nundinae (market day) and the period in between was known as a nundinum.
Each day of a nundial cycle was marked on a calendar with A-H (called nundial letters).
In addition to containing the nundial letters, Roman calendars also contained letter indicating the type of
public business that could be conducted on a certain day. These types of days included:
• Dies Fasti: “Sacred Days;” Lawsuits could be undertaken on these days.
• Dies Comitales: Days on which Roman assemblies could meet (they could not meet if this fell on the
nundinae or on certain feast days).
• Dies Nefasti: “Unholy Days”; the oppostie of dies fasti and comitales; lawsuits could not be undertaken
and assemblies could not meet.
• Dies Endotercissi: Days that were nefasti in the morning and evening; but fasti the rest of the time.
• Dies Religiosi: “Days of Ill Omen;” public business could not be taken up on these unless it absolutely
had to be.
• Dies Atri: “Black Days;” nothing could be done on these days; not even festivals.
• Dies Festi: Days on which festivals were held.
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The Romans had a rather laborious way of calculating days of the month. They had a series of “anchor dates”
from which they counted backwards to calculate the day to which they were referring.
One other oddity has to with how the Romans counted when calculating a date: when the Romans counted
backwards, they counted inclusively: This means they counted the current day as day number one. For
example, while we may consider “three days before Friday” to be Tuesday; the Romans would have considered
“three days before Friday” to be Wednesday (Friday day #1, Thursday day #2, and Wednesday day #3).
The three key “anchor dates” for the Romans were as follows:
- The Kalends (“Kal”): This Refers to the 1 st day of a month.
- The Ides (“Id.”): This refers to the middle day of a month; it fell on the 15 th in March, May, July, and August; in all other
months it fell on the 13 th .
- The Nones (“Non”): This term means “ninths;” it refers to nine days before the Ides; therefore it fell on the 7 th in March,
May, July, and August; in all other months it fell on the 5 th .
To indicate time before a certain date, the Romans used one of two phrases:
- pridie: this was only used to indicate the day before a certain day
- ante diem (a.d.): “the day before;” it is paired up with Roman numerals to indicate how many days before.
Examples of Roman dates for January: (Ides on the 13 th ; Nones on the 5 th ):
January 1 st : Kal. Ian. (The Kalends of January)
January 3rd: a.d. III Non. Ian. (3 days before the Nones of January)
Jaunary 5 th : Non. Ian. (The Nones of January)
January 8 th : a.d. VI Id. Ian. (6 days before the Ides of January)
January 13 th : Id. Ian. (The ides of January)
January 20 th : a.d. XIII Kal. Feb. (13 days before the Kalends of February)
January 31 st : pridie Kal. Feb. (the day before the Kalends of February)
Example of Roman dates for March (Ides on the 15 th ; Nones on the 7 th ):
March 1 st : Kal. Mart. (The Kalends of February)
March 3 rd : a.d. V Non. Mar. (5 days before the Nones of March)
March 7 th : Non. Mart. (The Nones of March)
March 8 th : a.d. VIII Id. Mart. (8 days before the Ides of March)
March 15 th : Id. Mart. (the Ides of March)
March 20 th : a.d. XIII Kal. Apr. (13 days before the Kalends of April)
March 31 st : pridie Kal. Apr. (the day before the Kalends of April)