The year 707 UAC, or 47 B.C.E., would be the final year of the pre-Julian era of the Republican Calendar II.
Before the Julian calendar would begin the following year, some calibration to the calendar needed to be done since the year began just two weeks after the autumnal equinox occurred, resulting in this calendar that was actually used mapping Ianuarius 1 to the modern-day proleptic Julian calendar in the first part of October in 47 B.C.E.
With the chaos of the civil wars of the Republic, the Romans in charge forgot to add the intercalary months, resulting in the calendar running way too fast!
This year already was extended from 355 to 378 days by the insertion of Mercedonius between Februarius and Martius. When Caesar, who was a high priest as well as a dictator of Rome, decreed the needed reform, probably in Quintillis (or July in later years), decided to add two extra leap months between November and December, totalling 67 days, to recalibrate the calendar so that December would fall where it should be in late fall to early winter instead of late summer to early fall. This made the following year begin at the right time again: that is, after the winter solstice.
The two extra months were called Intercalaris Prior and Intercalaris Posterior (not "Undecimber" and "Duodecimber"). Their individual lengths are unknown, as were the positions of the Nones and Ides within them.
This year, which was extended to 445 days, and was nicknamed annus confusionis or The Year of Confusion. This made the calendar year the longest in history.
In real time, people born at least 366 days before the end of that year during the same year actually passed their first birthdays in solar year time in the last 79 days of the same year! For people born during the three intercalaris months, their birthdates would simply disappear, never to be seen ever again, effectively, resulting in such people being forced to find a new day of the year to celebrate the anniversary of their birthdays. Some might have used a date in 45 B.C.E. that matches the date they were born 366 days before in 46 B.C.E. and celebrated their birthdays on the new dates on the Julian-Roman-Actual-1 calendars.
After this year ended, the Julian-Roman-Actual-1 (not the what is now the proleptic Julian-Roman-1 calendar as Caesar originally envisioned) began.
|Numeric Day of Month||Mart. Mai. Quin. Oct. (31 days)||no months (30 days)||Apr. Iun. Sext. Sept. Nov. Dec. Ian. (29 days)||Feb (23 days)||Mer. (28 days)|
|2||VI Non.||IV Non.||IV Non.||IV Non.||IV Non.|
|3||V Non.||III Non.||III Non.||III Non.||III Non.|
|4||IV Non.||Prid. Non.||Prid. Non.||Prid. Non.||Prid. Non.|
|6||Prid. Non.||VIII Id.||VIII Id.||VIII Id.||VIII Id.|
|7||Non.||VII Id.||VII Id.||VII Id.||VII Id.|
|8||VIII Id.||VI Id.||VI Id.||VI Id.||VI Id.|
|9||VII Id.||V Id.||V Id.||V Id.||V Id.|
|10||VI Id.||IV Id.||IV Id.||IV Id.||IV Id.|
|11||V Id.||III Id.||III Id.||III Id.||III Id.|
|12||IV Id.||Prid. Id.||Prid. Id.||Prid. Id.||Prid. Id.|
|14||Prid. Id.||XVIII Kal.||XVII Kal.||XVI Kal.||XVI Kal.|
|15||Id.||XVII Kal.||XVI Kal.||XV Kal.||XV Kal.|
|16||XVII Kal.||XVI Kal.||XV Kal.||XIV Kal.||XIV Kal.|
|17||XVI Kal.||XV Kal.||XIV Kal.||XIII. Kal.||XIII. Kal.|
|18||XV Kal.||XIV Kal.||XIII. Kal.||XII Kal.||XII Kal.|
|19||XIV Kal.||XIII Kal.||XII Kal.||XI Kal.||XI Kal.|
|20||XIII Kal.||XII Kal.||XI Kal.||X Kal.||X Kal.|
|21||XII Kal.||XI Kal.||X Kal.||IX Kal.||IX Kal.|
|22||XI Kal.||X Kal.||IX Kal.||VIII Kal.||VIII Kal.|
|23||X Kal.||IX Kal.||VIII Kal.||VII Kal.||VII Kal.|
|24||IX Kal.||VIII Kal.||VII Kal.||--||VI Kal.|
|25||VIII Kal.||VII Kal.||VI Kal.||--||V Kal.|
|26||VII Kal.||VI Kal.||V Kal.||--||IV Kal.|
|27||VI Kal.||V Kal.||IV Kal.||--||III Kal.|
|28||V Kal.||IV Kal.||III Kal.||--||Prid. Kal.|
|29||IV Kal.||III Kal.||Prid. Kal.||--||--|
|30||III Kal.||Prid. Kal.||--||--||--|