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Calendar 2: The Republican Calendar I

The Republican Calendar I (in use beginning from 700? B.C.E. until 453? B.C.E., or 54? UAC until 291? UAC)

References on the Internet disagree whether this version of the calendar was in use through 453 B.C.E. when revisions were instituted sometime between 452 and 450 B.C.E. inclusive. The beginning year is approximated to be 700 B.C.E. (54 UAC) though some sources give as early as 713 B.C.E. (41 UAC), but 715 B.C.E. (39 UAC) seems unlikely, when the reforms were made. I'll just leave these years with question marks for now.

The 304-day Romulus Calendar I didn't work as the years progressed since the calendar did not align with the seasons of the year.

The second King of Rome, Numa Pompilius (reigned 715-673 B.C.), reformed the calendar around the year 54 UAC, or 700 B.C.E., by shortening the months with 30 days (they'll be back to 30, or 31 for Sextilis and December, later), Aprillis, Iunius, Sextilis, September, November and December, to 29 days. He added the 29 day month of Ianuarius before Martius and made Ianuarius the start of the calendar, and added the 28 day month of Februarius after December and made Februarius the end of the calendar.

A day was taken from each month of 30 days, leaving the months with 31 days alone. The length of the calendar expanded from 304 to 355 days, with 11 or 12 days leftover.

Since the calendar was too short, and the Romans would rather have a full-year calendar instead of one that took a 61 to 62 day break, an intercalary month was instituted by Pompilius to be placed between Februarius and Ianuarius. The intercalary month would be called Mercedonius, or Intercalaris, with the meaning in Latin: mensis intercalaris, having 22 or 23 days depending on year, but with a catch.

Mercedonius was supposed to be inserted every two years or so to align the conventional 355-day Roman year with the solar year.

The catch? Mercedonius would have its 22 or 23 days placed after what is now known as February 23 (VII Kal.). The 22 days (or in some cases, 23 days) of Mercedonius would commence after February 23. After that, the five days of February that were displaced when Mercedonius was inserted would follow as part of Mercedonius to make it a 27 or 28 day month.

Since the Republican Calendars used the Kalends way of counting down to the following month, the days in Februarius would be called VI Kal. Ian (for Feb 24), V Kal. Ian (for Feb 25), IV Kal. Ian (for Feb 26), III Kal. Ian (for Feb 27) and pridie Kal Ian (for Feb 28).

When the last five days of Februarius became the last five days of Mercedonius, the days in that month would be called VI Kal. Ian (for Mer 23 or 24), V Kal. Ian (for Mer 24 or 25), IV Kal. Ian (for Mer 25 or 26), III Kal. Ian (for Mer 26 or 27) and pridie Kal Ian (for Mer 27 or 28).

I'm not sure if the truncated month of February still had the equivalent of Feb 23 as VII Kal Mer. or if it was changed to pridie Kal. Mer, but I'm guessing it wasn't called VII Kal. Ian since Ianuarius wasn't next on the intercalary calendar. I need to do more research on this.

The intercalary month was used to align the calendar with the solar year to create an average year of about 365 days over the course of time, with the years with the intercalary month expanded to either 377 or 378 days to counter the 355 day non-intercalary years.

The extra months were added arbitrarily at unpredictable intervals as determined by the pontifex maximus, the high priest of the College of Pontiffs in ancient Rome.

Some sources say February was cut short to 23 or 24 days with a 27 day Mercedonius taking over afterwards.

Mercedonius was supposed to occur every two years, but the Roman pontiffs in charge of it in later decades abused the timing for their own political purposes, resulting in the calendar going out of whack into the middle of the 1st century B.C.E.

Around the year 453 B.C., some adjustments to the order were made as we will see in the Republican Calendar II.

  1. This calendar cannot be proleptic, meaning, that it would not made sense if it was extended in either direction into the years it wasn't in existence earlier or employed in later years.
  2. the months on the Republican Calendar I: Ianuarius followed Februarius, in fact, the calendar began with Ianuarius but ended with Februarius, with the original ten months from Martius through December in order between the two months.
  3. The Month of February:
    1. February consisted of two parts, each with an odd number of days. The first part ended with the Terminalia on the 23rd, which was considered the end of the religious year, and the five remaining days, beginning with the Regifugium on the 24th, formed the second part.
    2. Terminalia was Feb 23, which was the end of the first part of February. Macrobius states that the year began after that day.
    3. the suppressed five days of Februarius are repurposed to be the last five days of Mercedonius, or VI Kal. Ian, V Kal. Ian, IV Kal. Ian, III Kal. Ian and pridie Ian, effectively leaving the last five Roman names of the days unchanged for this revision of the calendar.
    4. For 355 day years, Februarius had 28 days.
    5. For 377 day years:
      1. Februarius had 23 days and Mercedonius had 27 (22 inserted + five from Februarius)
      2. February XI (modern day Feb 14) to pridie Kal (modern day Feb 23), then, insert 22 days for the first days Intercalaris, then VI Kal to pridie Kal taken from February ended that month.
    6. For 378 day years:
      1. Some say that Februarius had 23 days and Mercedonius had 28 (23 inserted + five from Februarius). They argue that Mercedonius was of variable length of 27 or 28 days and Februarius was fixed at 23 during years with this intercalary month.
      2. Some say that Mercedonius had 27 with an inserted intercalary day after Feb 23 and Mercedonius 1
      3. Some say that Februarius varied from 23 days (for 377 day years) to 24 (for 378 day years) days and Mercedonius was fixed at 27 (23 inserted + four from Februarius)
      4. No date is offered for the Regifugium in 378-day years.
      5. Another source said that Mercedonius was inserted between Feb 23 and 24 and varied with a length of 22 days (for 377 day years) for 23 days (for 378 day years), with Feb 24-28 following the last day of Mercedonius.
    7. Possible Schemes for 378 day years:
      1. February XI (modern day Feb 14) to pridie Kal (modern day Feb 23), then, insert 23 days for the first days Intercalaris, then VI Kal to pridie Kal taken from February ended that month.
      2. February XII (modern day Feb 14) to III Kal (modern day Feb 23), then insert pridie Kal (modern day Feb 24), then, insert 22 days for the first days Intercalaris, then VI Kal to pridie Kal taken from February ended that month.
      3. February XII (modern day Feb 14) to pridie Kal (Modern day Feb 24), then, insert 23 days for the first days Intercalaris, then V Kal to pridie Kal taken from February ended that month.
  4. The Calendar Lineup:
    1. Ianuarius 29 (Nones on the 5th, Ides on the 13th)
    2. Martius 31 (Nones on the 7th, Ides on the 15th)
    3. Aprilis 29 (Nones on the 5th, Ides on the 13th)
    4. Maius 31 (Nones on the 7th, Ides on the 15th)
    5. Iunius 29 (Nones on the 5th, Ides on the 13th)
    6. Quintills 31 (Nones on the 7th, Ides on the 15th)
    7. Sextilis 29 (Nones on the 5th, Ides on the 13th)
    8. September 29 (Nones on the 5th, Ides on the 13th)
    9. October 31 (Nones on the 7th, Ides on the 15th)
    10. November 29 (Nones on the 5th, Ides on the 13th)
    11. December 29 (Nones on the 5th, Ides on the 13th)
    12. Februarius 28 in common years or 23 in intercalary years with its last five days following the 22 or 23 day intercalary month (Nones on the 5th, Ides on the 13th)
    13. Mercedonius (Intercalaris) 0 in common years or 22 or 23 in intercalary years, followed by the five days taken from Februarius to make it a 27 or 28 day month. (Nones on the 5th, Ides on the 13th)

Roman Day to Numeric Day of Month Equivalent Chart (700?-453? B.C.E.)

Months and Days added:
Februarius (28 days in month): Kal., IV Non. to Non., VIII Id. to Id., XVI Kal. to prid. Kal. (1st through 28th)
Februarius (23 days in month): Kal., IV Non. to Non., VIII Id. to Id., XVI Kal. to VII Kal. (1st through 23rd)
Ianuarius: Kal., IV Non. to Non., VIII Id. to Id., XVII Kal. to prid. Kal. (1st through 29th)
Mercedonius (27 days in month): Kal., IV Non. to Non., VIII Id. to Id., XV Kal. to prid. Kal. (1st through 27th)
Mercedonius (28 days in month): Kal., IV Non. to Non., VIII Id. to Id., XVI Kal. to prid. Kal. (1st through 28th)

Months and Days dropped:
Aprillis, Iunius, Sextilis, September, November, December (contracted from 30 to 29 days): XVIII Kal. (14th in 30 day calendar)

If people were born on the days that were seen in 701? B.C.E. or earlier, but are no longer seen, what days did they celebrate their birthdays in 700? B.C.E. and later?

Numeric Day of MonthMart. Mai. Quin. Oct. (31 days)no months (30 days)Apr. Iun. Sext. Sept. Nov. Dec. Ian. (29 days)Feb (28 or 23 days) Mer. (28 days)Mer. (27 days)
1Kal. Kal. Kal. Kal. Kal.
2VI Non. IV Non. IV Non. IV Non. IV Non.
3V Non. III Non. III Non. III Non. III Non.
4IV Non. Prid. Non.Prid. Non.Prid. Non.Prid. Non.
5III Non. Non. Non. Non. Non.
6Prid. Non. VIII Id. VIII Id. VIII Id. VIII Id.
7Non. VII Id. VII Id. VII Id. VII Id.
8VIII Id. VI Id. VI Id. VI Id. VI Id.
9VII Id. V Id. V Id. V Id. V Id.
10VI Id. IV Id. IV Id. IV Id. IV Id.
11V Id. III Id. III Id. III Id. III Id.
12IV Id. Prid. Id. Prid. Id. Prid. Id. Prid. Id.
13III Id. Id. Id. Id. Id.
14Prid. Id. XVIII Kal.XVII Kal. XVI Kal. XV Kal.
15Id. XVII Kal. XVI Kal. XV Kal. XIV Kal.
16XVII Kal. XVI Kal. XV Kal. XIV Kal. XIII. Kal.
17XVI Kal. XV Kal. XIV Kal. XIII. Kal.XII Kal.
18XV Kal. XIV Kal. XIII. Kal.XII Kal. XI Kal.
19XIV Kal. XIII Kal. XII Kal. XI Kal. X Kal.
20XIII Kal. XII Kal. XI Kal. X Kal. IX Kal.
21XII Kal. XI Kal. X Kal. IX Kal. VIII Kal.
22XI Kal. X Kal. IX Kal. VIII Kal. VII Kal.
23X Kal. IX Kal. VIII Kal. VII Kal. VI Kal.
24IX Kal. VIII Kal. VII Kal. VI Kal. V Kal.
25VIII Kal. VII Kal. VI Kal. V Kal. IV Kal.
26VII Kal. VI Kal. V Kal. IV Kal. III Kal.
27VI Kal. V Kal. IV Kal. III Kal. Prid. Kal.
28V Kal. IV Kal. III Kal. Prid. Kal.--
29IV Kal. III Kal. Prid. Kal.-- --
30III Kal. Prid. Kal.-- -- --
31Prid. Kal.-- -- -- --
  1. Id. = Idus = Ides
  2. Non. = Nonae = Nones
  3. Kal. = Kals = Kalendae
  4. Prid. = pridie
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