Roman Calendar

The Calendar that is used by many today was created and invented by the Romans.  The calendar did change a lot during Roman times.  The Emperor, Julius Caesar had the biggest impact on the calendar.

Romulus Calendar

Romulus created the first Roman Calendar in 753 BC.  Romulus created Rome and was a very important ruler.

His calendar had just ten months a year, started in March and was 304 days long.  The months had either 30 or 31 days in them.  There were 61 days of winter that were not counted in this Calendar.

March – 31 days

April – 30 days

May – 31 days

June – 30 days

July – 31 days

August – 30 days

September – 30 days

October – 31 days

November – 30 days

December – 30 days

First changes

The first change to the calendar was around 713 BC under the rule of Numa Pompilius.  He added two months to the calendar – January and February.  January had 29 days, and February had 28 days.

Pompilius also reduced the days for the months with 30 days to 29 days.  The months with 31 days stayed the same.  This meant that a year was now 355 days long.

March – 31 days

April – 29 days

May – 31 days

June – 29 days

July – 31 days

August – 29 days

September – 29 days

October – 31 days

November – 29 days

December – 28 days

January – 29 days

February – 28 days

The Romans did notice that the sun could make the year and the days longer.  To help with this, Pompilius had a ‘work month’ of 23 days added.

The month would be added between February and March.  This could take the full year to 377 days.

Julius Caesar

Under Julius Caesar, the Roman Calendar changed again in 46 BC.  He spoke with his scientists, and they believed that a full year was really 365 and a third.

This meant that a leap day needed to be added every three years.  Julius agreed to this and moved the start of the year to January.

This meant that every 3 years a day was added to the end of February. The number of days in the other months stayed the same


When Augustus came to power in 9 BC, he was told that the number of days for a full year was a little bit wrong.

Augustus was told that a full year is really 365 days and a quarter.  This meant that an extra day had to be added every four years.

Roman Calendar Facts

  • When Augustus changed the leap year to be every four years, he also missed out many years to let it catch up
  • The word calendar comes from the Latin word Kalendae.  This was what the Romans called the first day of every month
  • The Roman Calendar started in March because that was when farmers started to grow crops
  • In the first Roman Calendar, July was called Quintilis.  This was the Latin word for 5, and it was because it was the fifth month.  It was not renamed July until much later in memory of Julius Caesar.
  • The month after July was changed to August.  This was in memory of Augustus who followed Julius Caesar.
  • The Calendar that Julius Caesar created was not changed much until 1582
  • Most of the Roman months are named after the gods that they believed in.  March is from Mars, who was the god of war.  June is from Juno, who was the goddess of marriage and children
  • September, October, November, and December are just the names of the Roman numbers for 7,8,9 and 10.  These months were first the 7th, 8th, 9th and 10th months.  When the calendar was changed to make them the 9th, 10th, 11th and 12th months, they were just moved.

Roman Calendar Questions

  • How many months were there in the first Roman Calendar?
  • June is named after a goddess called Juno.  True or False?
  • In the first Roman Calendar’s, the year started in January.  True or false?
  • A work month could sometimes happen between February and March.  True or False?
  • September is the Roman name for the number 9.  True or False?
    False, it’s 7.