The Roman Calendar

Adjectival names of the months

Januarius, a, um
Februarius, a, um
Martius, a, um
Aprilis, e
Maius, a, um
Junius, a, um
Quin(c)tilius, e (before Julius Caesar's reforms); Iulius, a, um (after Caesar's reforms)
Sextilis, e (before 27 BCE); Augustus, a um (after 27 BCE)
September, bris, bre
October, bris, bre
November, bris, bre
December, bris, bre

Kalends, Nones, and Ides

	Most months	March, May, July, October
Kalendae, arum (f. plural):	1st	1st
Nonae, arum (f. plural):	5th	7th
Idus, uum (f. plural):	13th	15th

In March, July, October, May,
The Ides are on the fifteenth day,
The Nones the seventh; but all besides
Have two days less for Nones and Ides.

Describing dates

1. count inclusively backwards from next Kalends, Nones, or Ides
2. write ante diem (ordinal number), (Kalendas, Nonas, or Idus), (adjectival name of month): all in accusative
3. abbreviate a.d. (Roman numeral), (Kal., Non., or Id.), (abbr. name of month)
4. for the day before Kalends, Nones or Idus: pridie + Kalendas, Nonas, or Idus, adjectival name of month

Converting Roman Dates to our own

1. For days before Nones and Ides:

Add one to date of Nones or Ides, then subtract number given.

2. For days before Kalends:

Add two to total number of days in month, then subtract number given.

Examples

ante diem duodecimum Kalendas Iulias	June 20th
a. d. iv Non. Iul.	July 4th
Idus Martiae	March 15th
pridie Nonas Septembres	September 4th
ante diem octavum Kalendas Ianuarias	December 25th
a. d. x Kalendas Maias	April 22nd