The names of the 12 months that make up our Western calendar are so familiar that we do not think much about where they came from. The history of the calendar and the names of the months go back to the ancient Romans, with many modifications along the way.

Each 304-day, 10-month year began in the spring with March, when life begins its yearly cycle. Between the year ending in December and the new year in March was a festival period, which included the suspension of all war activities. The first day of March was the date of the first full moon after the end of the previous year regardless of when it occurred. This marked the resumption of war, so the month of March was named after the Roman god of war, Mars.

There has been much disagreement about the origins of the names for the other three months, April, May and June.

The Roman poet Ovid, writing around 30 B.C., said April was named Aprilis after a corrupted form of the Greek goddess Aphrodite. Others say it comes from the Latin “aperiere” (“to open”), suggesting the springtime budding of leaves and flowers, or the opening of the growing season. Some historians think that it may have come from an old Latin term for “after,” or “second.”

The origins of May and June are equally cloudy. They could have come from “Maia,” the goddess of growth, and Juno, queen of the gods, sister of Jupiter and patron of new brides. Other accounts suggest that these were months honoring grown men as in “maior” (major) and young men as in “junior.”

The last six months of the year were simply named by number: Quintillis (from Latin for five), Sextillia (from Latin for six), and the ones whose names remain today, September (seven), October (eight), November (nine) and December (10).

After Julius Caesar was assassinated in 44 B.C., Quintillis was renamed July in his honor, although some accounts suggest that he changed it to honor himself. Sextillia became August after Augustus became the first emperor of Rome, commemorating that several fortunate events of his life occurred during that month.

Even in Ovid’s time there was uncertainty about when January and February were added to the calendar, and in what sequence. It is generally believed that they were both added around 700 B.C. to fix the discrepancy between the 304-day, 10-month lunar calendar and the 365 days in the solar year.

January was the “gateway month,” named after Janus, the god of doorways and good beginnings, which the Romans thought ensured good endings. Janus is often depicted with a face on both the front and back of his head as he looks both inside and outside the entrance, suggesting both vigilance and fair-mindedness.

At first February came between the years after December, followed by January, then followed by March to start the next year.

Some time later they switched the order of January and February and adjusted the days in each month. It seems that February was always a short month, although lore has it that both Julius and Augustus “stole” days from it to make “their” months among the longest.

The name for February arises from the Latin word “februare,” meaning “to purify.” Some historians believe that a goatskin thong called a “februa” was used to gently thrash women with the belief that it would make them fertile. This ritual was performed during Lupercalia, the festival of fertility, which was held on the full moon, and gradually became associated with the feast day of St. Valentine, our Valentine’s Day.