How Did the Months Get Their Names?

The 12 Months of the Year and the Origins of Their Names

January 2, 2020
Old Calendar

How did the months of the year get their names? The months’ names reflect a mix of gods and goddesses, rulers, and numbers. This month, we focus on the month of October—but you can find your own birthday month listed here, too. 

Ancient Roman Calendar

Today we follow the Gregorian calendar, but it’s based on the ancient Roman calendar, believed to be invented by Romulus, the first king of Rome, around 753 BC.

The Roman calendar, a complicated lunar calendar, had 12 months but only 10 of the months had names. Basically, winter was a “dead” month when the government and military wasn’t active so they only had names for the time period we think of as March through December.

March was named for Mars, the god of war, because the this was the month when active military campaigns resumed! May and June were also named for goddesses (Maia and Juno). April meant “to open” in Latin, representing the opening buds of springtime. The rest of the months were simply numbered; their original names in Latin mean the fifth, sixth, seventheighthninth, and tenth month. Eventually, January and February were added to the end of the year so all 12 months had names.

Julian Calendar Updates

When Julius Caesar became pontifex maximus, he reformed the Roman calendar, so that the 12 months were based on the Earth’s revolutions around the Sun. It was a solar calendar as we have today. January and February were moved to the front of the year.

The winter months (January and February) remained a time of reflection, peace, new beginnings, and purification. After Caesar’s death, the month Quintilis (fifth) was renamed July in honor of Julius Caesar in 44 BC and, later, Sextilis (sixth) was renamed August in honor of Roman Emporor Augustus in 8 BC.

Of course, all the renaming and reorganizing meant that some of the months’ names no longer agreed with their position in the calendar (September to December). Later emperors tried to name various months after themselves, but those changes did not outlive them!

Today’s Gregorian Calendar

Eventually, the Julian Calendar was replaced with today’s Gregorian calendar because there were still some inaccuracies and adjustments to be made. For example, the calendar did not accurately reflect the time it took the Earth to orbit the Sun. 

The Month’s Names


Named for the Roman god Janus, protector of gates and doorways. Janus is depicted with two faces, one looking into the past, the other into the future. In ancient Roman times, the gates of the temple of Janus were open in times of war and closed in times of peace.


From the Latin word februa, “to cleanse.” The Roman calendar month of Februarius was named for Februalia, a festival of purification and atonement that took place during this period.


Named for the Roman god of war, Mars. This was the time of year to resume military campaigns that had been interrupted by winter. March was also a time of many festivals, presumably in preparation for the campaigning season.


From the Latin word aperio, “to open (bud),” because plants begin to grow in this month. In essence, this month was viewed as spring’s renewal.


Named for the Roman goddess Maia, who oversaw the growth of plants. Also from the Latin word maiores, “elders,” who were celebrated during this month. Maia was considered a nurturer and an earth goddess, which may explain the connection with this springtime month. 


Named for the Roman goddess Juno, patroness of marriage and the well-being of women. Also from the Latin word juvenis, “young people.”


Named to honor Roman dictator Julius Caesar (100 B.C.– 44 B.C.) after his death. In 46 B.C., Julius Caesar made one of his greatest contributions to history: With the help of Sosigenes, he developed the Julian calendar, the precursor to the Gregorian calendar we use today.


Named to honor the first Roman emperor (and grandnephew of Julius Caesar), Augustus Caesar (63 B.C.– A.D. 14). Augustus (the first Roman emperor) comes from the Latin word “augustus,” meaning venerable, noble, and majestic.


September comes from the Latin word septem, meaning “seven,” because it was the seventh month of the early Roman calendar.


In the ancient Roman calendar, October was the name of the eighth month of the year. Its name comes from octo, the Latin word for “eight.” When the Romans converted to a 12-month calendar, they tried to rename this month after various Roman emperors, but the name October stuck!

In Old England, the month was called Winmonath, which means “wine month,” for this was the time of year when wine was made. The English also called it Winterfylleth, or “Winter Full Moon.” They considered this full Moon to be the start of winter. In weather lore, we note, “If October brings heavy frosts and winds, then will January and February be mild.”

Read more about the meaning of October.


From the Latin word novem, “nine,” because this had been the ninth month of the early Roman calendar.


From the Latin word decem, “ten,” because this had been the tenth month of the early Roman calendar.

Now that you know more about our month’s names, how about the day’s names—Monday, Tuesday, etc.? For the truly curious calendar lovers, check out the origin of day names.


This article was originally published in 2009 and has been updated.


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Happy missday for any wife& amaricans woman♡♡♡♡



When is harvest moon

When is harvest moon

The Full Harvest Moon will

The Editors's picture

The Full Harvest Moon will occur on September 19, 2013, at 7:13 a.m. EDT.