The English calendar is customary rather than logical. It is inherited from Classical Rome via the Latin-Christian culture that once controlled education. The Romans originally had a hybrid system, with months matching the actual waxing and waning of the moon, but an extra February added when the system was obviously out of step with the solar year. The Late Republic let this slip, showing a superstitious dread of risking a double dose of a month traditionally considered unlucky.
Julius Caesar’s reform broke their link to the moon but kept the month-names. With minor changes, this system is still our system:
- January, from Janus, the god of gates and doorways.
- February, from Februa, a Roman festival of purification held then.
- March, from the war-god Mars.
- April, uncertain, maybe based on the opening of flowers.
- May, probably from the Greek goddess Maia. She was identified with the Roman-era goddess of fertility, Bona Dea, whose festival was held in May. Alternatively, the month was named for elders.
- June, probably for the goddess Juno, but possibly a month for the young, to follow the celebration of elders in May.
- July from Julius Caesar, who was deified by Emperor Augustus.
- August from Augustus, deified by his successor Emperor Tiberius.
- September, October, November and December – months 7, 8, 9 and 10.
The Roman system must have been built by a merger of some even older traditions. They used the December/January split for an annual change of Consuls and other important officials. And since they identified years by the ruling Consul, this became the end and beginning of years. But there must also have been a notion that the old year ended in February and begin again in March. So naming months 7, 8, 9 and 10 made sense, as did the former names of July and August as 5 and 6, Quintilis and Sextilis.
We have the little-loved Emperor Tiberius to thank, for not having a run of bad English puns between July and September.
An uncertainty over the year’s actual beginning lasted some time in the Latin Christian tradition. Many felt it should be March/April, which is still commonly used for the Financial Year. Chaucer’s Canterbury Tales, The Merchant’s Tale has ‘Old January’ married to a young and unfaithful lady called May. Nowadays we’d say May and December for a marriage mismatched by age.
Days of the week also reflect Roman paganism, and a much older tradition going back to the high days of Babylon, or possible before. A seven-day week is derived from the sun, moon and the five planets known to them.
They could have known more. Both Uranus and the asteroid Vesta can be seen as faint stars by someone who has dark skies and knows exactly where to look. But as far as we known, no one did notice them until they were discovered by telescope. After their discovery, it was realised that earlier astronomers had recorded them as faint stars when they were making sketches centred on something else. They failed to notice that this faint star was moving from day to day. No one back then bothered with recording the positions of the fainter and seemingly insignificant stars. This missed opportunity shows why there is great merit in collecting a mass of raw data even without any particular expectation of finding anything.