The Roman calendar
According to Roman tradition, the earliest calendar of Rome had only ten months, starting in March and ending in December, with the winter period left out of the count. Two more months, January and February, were later added, traditionally credited to the king Numa Pompilius.
Over time the Romans came to begin their civil year on 1 January. In 46 BC, Julius Caesar reformed the calendar, creating the Julian calendar with 365 days and a leap day every four years. The months and their lengths then were essentially the ones still used today. Read more about that reform in what is a leap year.
Month by month
| Month | Named after | Meaning |
|---|---|---|
| January | Janus | Roman god of doors, gates and beginnings |
| February | Februa | A Roman purification festival held in this month |
| March | Mars | Roman god of war |
| April | Aprilis | Uncertain origin |
| May | Maia | A goddess linked with growth |
| June | Juno | Queen of the Roman gods |
| July | Julius Caesar | Renamed in his honor |
| August | Augustus | Renamed in honor of the first emperor |
| September | septem | Seven |
| October | octo | Eight |
| November | novem | Nine |
| December | decem | Ten |
January to June
January honors Janus, the two-faced god who looks both backward and forward, a fitting patron for the start of a year.
February comes from februa, the Roman rites of purification held in the middle of the month. For a long time it was the last month of the Roman year, and it remains the shortest.
March is named after Mars, the god of war. It was the first month of the oldest Roman calendar, and spring was when military campaigns traditionally began.
April is the hardest to explain. The Romans themselves were unsure. One old idea links it to the Latin verb aperire, to open, as buds open in spring; another links it to the goddess Aphrodite. Neither is certain.
May is usually linked with Maia, a goddess associated with growth and the earth.
June is usually linked with Juno, the queen of the gods and protector of women and marriage.
July and August
The fifth and sixth months of the old March-based calendar were originally called Quintilis and Sextilis, meaning fifth and sixth. In 44 BC, the year of Julius Caesar’s assassination, Quintilis was renamed Julius in his honor, since he was born in that month. In 8 BC, Sextilis was renamed Augustus after the first Roman emperor, giving us August.
September to December
The last four months still carry their old numbers: September (seven), October (eight), November (nine) and December (ten). The numbers made sense when the year began in March. Once the year was counted from January, each one ended up two places later than its name suggests.
From Latin to English
The Latin names passed into English, partly through Old French, and gradually took their modern spellings. Old English had its own month names before the Roman ones took over, but they gradually fell out of use.
Many other European languages use similar forms: French janvier, Spanish enero, German Januar and Italian gennaio all come from the same Latin root.
Months and seasons
Because the Gregorian calendar is tied to the seasons, each month falls in roughly the same part of the year every year: June is in summer in the northern hemisphere and in winter in the southern hemisphere. Learn how the calendar maps to the year on the seasons page, see every month laid out in the 2026 calendar, or read about the origin of the days of the week.