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Click to Select a Page... Main Page Calendar 1: The Romulus Calendar I Calendar 2: The Republican Calendar I Calendar 3: The Republican Calendar II Calendar 4: The Republican Transitional Calendar Calendar 5: The Julian-Roman-Actual-1 Calendar Calendar 6: The Julian-Roman-Transitional-1 Calendar Calendar 7: The Julian-Roman-1 Calendar Calendar 8: The Julian-Kalends-1 Calendar Calendar 9: The Julian-1 Calendar Calendar 10: The Gregorian Calendar February Notes Dual Dating Date Confusion Definition of Days on the Calendars Definition of Calendars: Others Old, New and Unknown Styles Use of Offset by One Day Calendars Leap Year Error on the Julian-Roman-Actual-1 Calendar What Calendars Each Country Was Using Gregorian-Julian Differences By Century New Years Days Addenda Day and Year Measurements Calendar Varieties-Gregorian Calendar Varieties-Julian Calendar Varieties-Other Years Converted From Julian Period Day Lining Up Julian Dates Between Earth and Mars The Martian Calendar of Earth Converting From the Julian Period Date Creating a Julian Period Day Database File Truncating Answers Conversion Between Julian-1 and Gregorian Calendars Create a Calendar Leap Year Day Comparisons Swedish Calendar 1700-1712 Fractions of Years, Etc. Dave's Fun Stuff's Stuff Green Concepts Jesus' Date of Conception Calendar Coincidence Calendar History Units of Time Food to Lower Blood Pressure Fun With Money Electricity Rates Optical Illusions Celebrity Autographs Eat More Potassium! TV Died State Abbreviations Volume Measurements The 21 Factory Fun With Math Strip Unicode Mesa Silicon Cajon Dave's Fun Stuff Find your favorite TV shows with "Let's Watch TV!" Dave's Fun Stuff SDN Media News and More Dave's Fun Stuff Super Birthdays

February Notes

The month of February, or Februarius as it was originally called, has a complex set or rules during the Roman era of calendars regarding inserting intercalating days to line up the calendar's place with the Earth's place regarding lining up the seasons so that the seasons change near the expected seasonal change points on the calendar.

To make a long story short, in the beginning, there was an intercalary month inserted between the modern February days of the 23rd and 24th to slow down the calendar due to the fact that the older calendars were short by around 11 or 12 days each year, and the calendar masters were charged to make sure that an intercalary month was inserted every few years. When the Julian (and later Gregorian) calendars were introduced to reform the Roman calendar, the idea of a leap month inserted into February was abandoned in favor of inserting an intercalary day between the days of February 23rd and 24th every four years, and with the Gregorian calendar introduction, three out of every four years that are multiples of 100 and not 400 are non leap years.

While the modern day Julian day calendars (with numbers for the days of the month) and Gregorian calendars, the intercalary day was tagged between February 28 and March 1 instead of between February 23 and 24. One idea was to borrow an idea from the older Roman and Julian calendars was to have the intercalary day moved to after February 23 and call it February 24 Posterior, but it would cause too much confusion and was abandoned in favor of having the February 29 as the Bissextile Day for modern day calendars, but in reality, during leap years, the intercalary day would be on February 24, but the normal non-leap years of February 24 through the 28th would be called February 25 through February 29 during leap years so that the numbers would be in numerical order I suppose.

Let's go back to the older Julian calendars and assume that February, or Februarius, always had 28 days, with the 29th day added during leap years. First, some terminology is in order.

Quirina'lia is on February 17. (a.d. XIII Kal. Mar.) It's the date of an annual religious festival sacred to Quirinus. According to Roman history, it's the day which Romulus (Quirinus) was carried into Heaven.

Feralia is on February 21. (a.d. IX Kal. Mar.) It's the date of an ancient Roman public festival celebrating the Manes.

Caristia is on February 22. (a.d. VIII Kal. Mar.) It's a potluck meal provided by all the family, and shared in a spirit of love and forgiveness

Terminalia is on February 23. (a.d. VII Kal. Mar.) It's the date of an ancient Roman festival in honor of the god Terminus, who presided over boundaries, hence the name, meaning terminate, as in, this is the last day of the first part of February.

Regifugium is on February 24. (a.d. VI Kal. Mar.) It's a festival which is celebrated by the Romans every year on the 24th of February, and is Latin for "Flight of the King." It was viewed by the Romans of the Republic as an "Independence Day" as well as the start of the second part of February.

Equirria is on February 27. (a.d. III Kal. Mar.) It's the first of two horse-racing festivals to Mars, the god of War.

The original New Year's Day is on March 1 (a.d. Kal. Mar.) It's the day when the sacred fire of Rome was renewed.

a.d. days are ante diem. For example, Februarius 24 would be ante diem sextum Kalendae Martius, or a.d. VI Kal. Mart.

During Leap Years...

Bissextile is a group of two days that overlap the intercalary day with the day after it, or a.d. VI Kal. Mart. It would be inserted on the day after modern day February 23, or a.d. VII Kal. Mart., as opposed to the day after modern day February 28, or a.d. prid. Kal. Mart., causing confusion with the dates of festivals and traditions and the start of the month of Martius (a.d. Kal. Mart.)

So for teaching purposes only, let's call the intercalary day February 23.9... to keep the dates in order, with the .9's extending into infinitecimal, making it almost like a second February 24, but here's how to teach about intercalation during the early Julian calendar days, as well as the corresponding Kalendae naming.

To recap...

February 23 (a.d. VII Kal. Mar.) is the last day of the first part of February.

Now...this...

February 23.9... old Julian (a.d. (bis) VI Kal. Mar.) (Feb 24 modern Julian/Gregorian day during leap years) is the intercalary day, and is the first of two days that make up Bissextile (or as I call it the Bissextile Duo). This day is called Bissextile Day, also known as Bissextus posterior, Bissextum, or Intercalary Day. This is the calendar's Leap Year Day, or ante diem bis sextum Kalenda Martius. It's also the start of the second part of Febuarius. This is the traditional spot where an extra day for leap years is inserted every February 24, forcing the non-leap year days to move down one day to February 25 through 29. Got that so far?

February 24 old Julian (a.d. VI Kal. Mar.) (Feb 25 modern Julian/Gregorian day during leap years) is the second of two days of the Bissextile Duo. It's also called Bissextus prior during leap years only. Regifugium always falls on a.d. VI Kal. Mar. each year as a result of the placement of the intercalary day so that the traditional Roman festivals flow from the last day in Febuarius to the first day of Martius without a one-day leap year day delay. Hope this is clear.

February 25 old Julian (a.d. V Kal. Mar.) (Feb 26 modern Julian/Gregorian day during leap years)

February 26 old Julian (a.d. IV Kal. Mar.) (Feb 27 modern Julian/Gregorian day during leap years)

February 27 old Julian (a.d. III Kal. Mar.) (Feb 28 modern Julian/Gregorian day during leap years)

February 28 old Julian (a.d. prid. Kal. Mar.) (Feb 29 modern Julian/Gregorian day during leap years)

March 1 (both old and new Julian and Gregorian calendars) (a.d. Kal. Mar.)

During Non Leap Years...

February 23 (both old and new Julian and Gregorian calendars) (a.d. VII Kal. Mar.)

February 24 (both old and new Julian and Gregorian calendars) (a.d. VI Kal. Mar.)

February 25 (both old and new Julian and Gregorian calendars) (a.d. V Kal. Mar.)

February 26 (both old and new Julian and Gregorian calendars) (a.d. IV Kal. Mar.)

February 27 (both old and new Julian and Gregorian calendars) (a.d. III Kal. Mar.)

February 28 (both old and new Julian and Gregorian calendars) (a.d. prid. Kal. Mar.)

March 1 (both old and new Julian and Gregorian calendars) (a.d. Kal. Mar.)

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Calendar History Main Page Calendar 1: The Romulus Calendar I Calendar 2: The Republican Calendar I Calendar 3: The Republican Calendar II Calendar 4: The Republican Transitional Calendar Calendar 5: The Julian-Roman-Actual-1 Calendar Calendar 6: The Julian-Roman-Transitional-1 Calendar Calendar 7: The Julian-Roman-1 Calendar Calendar 8: The Julian-Kalends-1 Calendar Calendar 9: The Julian-1 Calendar Calendar 10: The Gregorian Calendar February Notes Dual Dating Date Confusion Definition of Days on the Calendars Definition of Calendars: Others Old, New and Unknown Styles Use of Offset by One Day Calendars Leap Year Error on the Julian-Roman-Actual-1 Calendar What Calendars Each Country Was Using Gregorian-Julian Differences By Century New Years Days Addenda Day and Year Measurements Calendar Varieties-Gregorian Calendar Varieties-Julian Calendar Varieties-Other Years Converted From Julian Period Day Lining Up Julian Dates Between Earth and Mars The Martian Calendar of Earth Converting From the Julian Period Date Creating a Julian Period Day Database File Truncating Answers Conversion Between Julian-1 and Gregorian Calendars Create a Calendar Leap Year Day Comparisons Swedish Calendar 1700-1712 Fractions of Years, Etc.
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