Where the names of the months and days come from
Updated
The English calendar is a Roman year with a Germanic week. The months carry the names of Rome's calendar; the days carry the names of seven planets, four of them swapped for Anglo-Saxon gods.
Ten months, then twelve
By Roman tradition, the first calendar, attributed to Romulus, had ten months. It began in spring with Martius and ended with December. His successor Numa Pompilius divided the year into twelve lunar months by adding two winter months, Ianuarius and Februarius.
What the month names mean
| Month | Latin | Named after |
|---|---|---|
| January | Ianuarius | The god Janus |
| February | Februarius | Februa, rites of purification |
| March | Martius | Mars |
| April, May, June | Aprilis, Maius, Iunius | Uncertain |
| July | Iulius (was Quintilis, "fifth") | Julius Caesar |
| August | Augustus (was Sextilis, "sixth") | The emperor Augustus |
| September to December | September … December | Seventh to tenth |
Quintilis to December are old Latin ordinal numbers, five to ten: their places in a year that began around the spring equinox. That is why September, "seventh", is now the ninth month, and December, "tenth", the twelfth. After Caesar's assassination, Mark Antony had Caesar's birth month, Quintilis, renamed July; in 8 BC Sextilis was renamed August in honour of Augustus. Why the year now starts with January is in why New Year is on 1 January.
Seven planets, seven days
In a great many languages the days of the week are named after the seven classical planets: the Sun, the Moon, Mars, Mercury, Jupiter, Venus and Saturn. The Roman Empire took up this planetary week in late antiquity. French still shows the pattern: lundi is the Moon's day, mardi Mars's, mercredi Mercury's, jeudi Jupiter's and vendredi Venus's.
English swapped in its own gods
English kept the Sun and the Moon — Old English Sunnandæg, "sun's day", and Mōnandæg, "Moon's day" — and Saturn in Saturday, from the Latin diēs Sāturnī. The four days in between took Germanic gods instead of Roman ones:
- Tuesday, Tīwesdæg: the day of Tiw, the Norse Týr
- Wednesday, Wōdnesdæg: the day of Woden, the Norse Óðinn
- Thursday, Þūnresdæg: the day of Þunor, the Norse Thor
- Friday, Frīgedæg: the day of the goddess Frīg
The Germanic names were adopted some time after 100 AD and before the conversion to Christianity in the 6th and 7th centuries; the exact date is not known.
What changed later
The names stayed, but the calendar under them was corrected. In September 1752 Britain skipped eleven days to catch up with most of Europe; the story is in the year Britain skipped eleven days.
Sources
- Roman calendar — Wikipedia (Romulus's ten months, Numa's twelve, month-name origins, July and August renamed)
- Names of the days of the week — Wikipedia (the seven classical planets, Old English day names, French names, dating)