Roman Calendar

  • The Roman Calendar was a Lunar Calendar of 304 days divided into 10 months of roughly 30 days, but eventually the Seasons no longer coincided with the calendar.
  • n 45 BCE a solar calendar was introduced called the Julian Calendar, which we still use today.

The Roman Dating System: AUC

  • The Roman Calendar used a dating system called AUC meaning Ab urbe condita.
  • The Romans counted their years ‘from the Founding of the City of Rome’ in 793 BCE, known in Latin as ‘Ab urbe condita’.

The Calendar of the Roman Kings

  • In c.738 BCE Romulus instituted a Roman Calendar of ten months with 304 days, starting with Martius. It was missing 61.25 days, and very soon Winter and Summer no longer coincided with the Calendar.
  • Numa Pompilius (715-673 BCE) then added two months to the Calendar, Januarius at the beginning and Februarius at the end, to make 12 months of 355 days.
  • 452 BCE Februarius was moved between Januarius and Martius.
  • 452 BCE Every second year, an Intercalary month named ‘Intercalaris’ of 22 or 23 days was inserted after 23rd of Februarius. The remaining days of Februarius were added at the end. (This month may have been added earlier under Numa and called ‘Mercedinus’, the Sources vary)

The Julian Calendar (45 BCE)

  • In 45 BCE, the Roman Calendar was reformed under Julius Caesar to become the Julian Calendar. This was a solar calendar of 365 days with an extra day in February every fourth (leap) year.
  • The Gregorian Calendar replaced the Julian Calendar in 1582 CE and is named after Pope Gregory XIII.
  • The Julian Calendar and the Gregorian Calendar have exactly the same number of months and the same number of days in each month. But in the Gregorian Calendar, Leap Years ending in 100 are not Leap Years, unless the number is divisible by 400.

The Roman Year of 12 months

  1. Januarius (Janus.)
  2. Februarius (Festival of Februa.)
  3. Martius (Mars.) 31
  4. Aprilius (from either ‘Aperit’ to open, or ‘Aphrodite’.)
  5. Maius (Maia.) 31
  6. Junius (Juno)
  7. Julius (Julius Caesar) 31
  8. Augustus (Augustus Caesar)
  9. September (Seventh)
  10. October (Eighth) 31
  11. November (Ninth)
  12. December (Tenth)
    • Saturnalia: 17th-25th A week of celebration where slaves did not have to work.

The Roman Month: Kalends, Nones and Ides

  • The Romans originally divided the month into three sections of the Eight Phases of the Moon.
    • The Kalends
      • This was the first observation of the visible new moon’s crescent.
    • The Nones
      • The days were then counted down to the Nones, which was the first quarter Moon.
    • The Ides
      • The Ides was the full Moon. The longest countdown then started to the first observation of the visible crescent of the following month’s moon, the next Kalends.
  • Introduction of Fixed Days of the Month
    • In the fifth century BCE, the Romans ceased correlating the Moon Phases with the Calendar, and instead used fixed days of the month.
    • The Ides was held on the 15th of all months containing 31 days, (March, May, July, October) and on the 13th of all the other months.
    • So, Beware the Ides of March, meant beware the 15th of March.
    • The Ides section always had 8 days, but the Nones section had either 4 or 6 days, and the Kalends section had from 16 to 19 days.
    • Kalends of Januarius. (First thin crescent of the Moon.)
      • IV days befor the Nones of Januarius.
      • III days befor the Nones of Januarius.
      • The day before the Nones of Januarius.
    • Nones of Januarius. (First Quarter Moon)
      • VIII days before the Ides of Januarius.
      • VII days before the Ides of Januarius.
      • VI days before the Ides of Januarius.
      • V days before the Ides of Januarius.
      • IV days before the Ides of Januarius.
      • III days before the Ides of Januarius.
      • The day before the Ides of Januarius.
    • Ides of Januarius. (Full Moon)
      • XIX days before the Kalends of Februarius.
      • XVIII days before the Kalends of Februarius.
      • XVII days before the Kalends of Februarius.
      • XVI days before the Kalends of Februarius.
      • XV days before the Kalends of Februarius.
      • XIV days before the Kalends of Februarius.
      • XIII days before the Kalends of Februarius.
      • XII days before the Kalends of Februarius.
      • XI days before the Kalends of Februarius.
      • X days before the Kalends of Februarius.
      • IX days before the Kalends of Februarius.
      • VIII days before the Kalends of Februarius.
      • VII days before the Kalends of Februarius.
      • VI days before the Kalends of Februarius.
      • V days before the Kalends of Februarius.
      • IV days before the Kalends of Februarius.
      • III days before the Kalends of Februarius.
      • The day before the Kalends of Februarius.
    • Kalends of Februarius.

The Roman Week

  • The 7 Day Roman Week:
    • Sun’s day (Sunday) dies Solis
    • Luna’s day (Monday) dies Lunae
    • Mars’ day (Tuesday) dies Martis
    • Mercury’s day (Wednesday) dies Mercurii
    • Jupiter’s day (Thursday) dies Jovis
    • Venus’ day (Friday) dies Veneris
    • Saturn’s day (Saturday) dies Saturni

The Roman Day

  • The 24 hour Roman Day:
    • There were 24 hours in a Roman day, which ran from from midnight to midnight, and was divided into 12 hours of day and 12 hours of night. The Roman day started at sunrise and ended at sunset, when the Roman Night began.
    • But unlike today, the 12 hours of day were measured from sunrise to sunset all year round, so they did not always have 60 minutes in each hour. The hours were numbered ‘hora prima, hora secunda, hora tertia’, and so on.
    • Roman Time was only measured by the hour, not in minutes and seconds as today.
  • The 16 part Roman Day:
    • Media nox (midnight)
      • Mediae noctis inclinatio (after midnight)
      • Gallicinium (cock crow)
      • Conticinium (cock stops crowing)
    • Diluculum (dawn)
      • Mane (morning)
      • Antemeridianum tempus (before noon)
    • Meridies (Noon)
      • Tempus pomeridianum (after noon)
      • Solis occasus (sunset)
      • Vespera (evening)
    • Crespusculum (twilight)
      • Prima fax (candle lighting)
      • Concubia nox (bedtime)
      • Intempesta nox (late in the night)
      • Inclinatio ad mediam noctem (before midnight)

The Lunar Calendar

  • The Lunar cycle (around the Earth) lasts for 29 1/2 days (29 days, 12 hours, 44 mins)
  • The Lunar calendar compensates for the half day by making one month 29 days and the next month 30 days.
  • A Lunar year consists of 12 cycles, consisting of 354 days and 8 hours.
  • This means the Lunar calendar loses 11 days, compared with the Solar year of 365 days.
  • It takes 33 lunar years for the Lunar calendar to return to the same point in the Solar calendar.

The Lunisolar Calendar

  • This is a calendar that combines the lunar cycles with the solar year.
  • An example is the Coligny Calendar from the 2nd century CE, based on a five year cycle.

 

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