HOW TO CALCULATE AND USE THE CALENDAR

I know this could be obvious to most, but I'm sure there are a lot of people who can't read roman numerals. Here I will explain the pattern in this number expression and how to do it.

The roman numerals are ordered in a sequence of numbers that are repeated thrice and numbers that are not repeated. "I" is the number for 1. It is repeated twice more as "II" (2) and "III" (3). The repeating numbers only repeat thrice, so there is no "IIII". To make the fourth sequenced number, you get the fifth one (V, 5) and put before it the amount that, subtracting from the fifth, becomes the fourth. In this case, "IV" is 4. Because 5 – 1 = 4. After that is V as I said (5). The process then repeats with the V as a marker. 6 is "VI" (5+1). "VII" is 7. "VIII" is 8. There is no "IIII" as we said before, nor is there any repetition of "V", so we need a new number symbol to represent 9. We use in this case the same logic as before, with an "X" representing 10 and a "IX" (10-1) representing 9. 20 would then be "XX". 30 "XXX". 38 would be "XXXVIII" and 39 "XXXIX". 40 would be 50 – 10. 50 being "L", so 40 is "XL". This same process repeats on and on, with repeating and non repeating numerals in alternation. These numerals are:

I – 1 (repeats)
V – 5 (doesn't repeat)
X – 10 (repeats)
L – 50 (doesn't repeat)
C – 100 (repeats)
D – 500 (doesn't repeat)
M – 1000 (repeats)

This year, in Ab Urbe Condita (AUC) would then be MMDCCLXIX (2769).

First thing we need to get out of the way is this strange method of counting that the romans used. It is called 'inclusive counting' and, as the name implies, it is when you don't only count the days till the given date, but also the day itself. If today is the 1st of November and you wanted to count till the 5th, you'd usually say it is "4 days till the 5th". That is because we do not count the day itself inside the count. The romans did. So if you were on the 1st and wanting to count till the 5th, a roman would say that it is "5 days till the 5th". If you were in the 3rd and counting till the 8th, a roman would say it is "6 days till the 8th" instead of 5.

There are two starts of the roman year. One civil and one religious. The civil year starts in the 1st of Ianuarius (January). The religious year starts after the festival of the Terminalia (the Terminalia being on the 23rd of Februarius or February).

Two months have different names depending on the tradition you follow. July can be named either Quintilis (the original name of the month) or Iulius (named in honor of the Divus C. Julius Caesar). August can be named either Sextilis (the original name of the month) or Augustus (named in honor of the Divus Imperator Caesar Augustus).

The names of the months, their abbreviation and their corresponding gregorian month are:

Ianuarius – Ian. – January
Februarius – Feb. – February
Martius – Mar. – March
Aprilis – Apr. – April
Maius – Mai. – May
Iunius – Iun. – June
Quintilis/Iulius – Quin./Iul. – July
Sextilis/Augustus – Sex./Aug. – August
September – Sept. – September
October – Oct. – October
November – Nov. – November
December – Dec. – December

The romans did not count as us, from the 1st to the 28th/29th/30th/31st of the month. They divided up the month in three parts and counted to those days. Those parts were the Kalends, the Nones and the Ides.

The Kalends is the first day of the month. The Nones can be either the 5th or the 7th day of the month. The Ides can be either the 13th or the 15th of the month.

The Nones and Ides are on the 7th and the 15th in March, May, July and October. They are on the 5th and the 13th in all other months.

The count of days is done, in most cases, by counting the days before that given day or by saying that given day. The 1st of January would then be written as "Kal. Ian.", the Kalends of Ianuarius. The day after that is, in inclusive counting, 4 days before the Nones of Ianuarius, expressed in latin as "a.d. IV Non. Ian." In which "a.d" means "ante diem" or "before the day". The day BEFORE any of the three marks (Kalends, Nones, Ides) are not marked by a number, but by the word "pridie" or "day before" abbreviated as "pr." So the 4th of January is not "a.d. II Non. Ian." but instead "pr. Non. Ian." The day after the Ides is counted by the Kalends of the next month. The 14th of January would then be "a.d. XXVIII Kal. Feb."

The romans used many different manners to count the years. The most famous of them is the Ab Urbe Condita (a.u.c.), the time From the Founding of the City [of Rome]. But it must be said that the a.u.c. was almost never used to mark dates . It was used primarily to count time between dates.

Consular Year – The form in which romans generally marked years was with the Consular Year, the year in which this and that persons were Consuls. To do so, you state the abbreviated form of the praenomina and Nomina (first and second name) of the Consuls of that year on the Dative Case (men usually ending in -o instead of -us and women ending in -ae instead of -a) together with the word "Consulibus" abbreviated as "cos." The year 2016 CE in the Roman Republic is, for example, T. Flavio P. Iunio cos., which means "Titus Flavius and Publius Iunius being Consuls". Since it is versed as such, one does not say "this happened in T. Flavio P. Iunio cos.", but simply "this happened T. Flavio P. Iunio cos." This form of dating would be the one used in most official documents.

Olympiads – This form of dating was used when speaking of the time before the founding of Rome. It counts a period of 4 years from one Olympic Game to the next and would be used counting either the number of the Olympiad or the name of the Victor of one of the games (usually the Stadium). Dyonisius of Halicarnasus, foi example, dates the founding of Rome at 752 BCE by saying that it happened "in the first year of the seventh Olympiad", which could also be said as "the year in which Deocles of Messenia won at the Stadium" or "In the first year of the Olympiad in which Deocles of Messenia won at the Stadium".

If we take the day of this publication (July 10th 2016 CE) and converted it to roman standards it would be written as so:

a.d. VI Id. Iul. T. Flavio P. Iunio cos.