Why does your week worship five dead gods?

luni to vineri: what the dictionaries say

Five gods, five working days

Romanian keeps the Latin planetary week almost untouched from Monday to Friday. The dictionary explains each name through its planet's day: [dies] Lunae, Martis, Mercuris, Jovis, Veneris.

luni lunae

the Moon

Luni comes from [dies] Lunae, the day of the Moon. DEX cites the form lunis, that is lunae, and points to the Moon. It is the only day named after a heavenly body you can see with open eyes on any clear night.

marți martis

Mars

Marți comes from [dies] Martis, the day of Mars, god of war. DEX gives plain martis [dies]. French mardi and Italian martedì keep the same god.

miercuri mercuris

Mercury

Miercuri comes from [dies] Mercuris, the day of Mercury, messenger of the gods. DEX gives mercuris [dies]; the Candrea dictionary also records the variant MERCURII DIES. The fastest god holds the middle of the week.

joi jovis

Jupiter

Joi comes from [dies] Jovis, the day of Jupiter, master of the gods. DEX gives Lat. [dies] Jovis. French jeudi and Spanish jueves keep the same supreme god.

vineri veneris

Venus

Vineri comes from [dies] Veneris, the day of Venus, goddess of love. DEX gives Lat. Veneris [dies]. The working week ends with the gentlest goddess.

Why the gods stand scrambled

The arithmetic that scrambled the week

The planets had a fixed ladder, from the slowest to the fastest: Saturn, Jupiter, Mars, Sun, Venus, Mercury, Moon. Each hour of the day belonged, in turn, to one planet, and the planet of the first hour named the day. A day holds twenty-four hours, and twenty-four means three full rows of seven plus three hours. So each day starts three rungs lower on the ladder, and the row of days comes out scrambled.

24 = 3×7+3

The Chaldean ladder, from the slowest planet to the fastest:

1. ♄ Saturn
2. ♃ Jupiter
3. ♂ Mars
4. ☉ Sun
5. ♀ Venus
6. ☿ Mercury
7. ☽ Moon

Run the hoursOne hour furtherFrom the start

Day display order:

ancient, from Saturday modern, from Sunday modern, from Monday

Hour 1 of 168: Saturn rules the hour; Saturday belongs to Saturn.

The day rulers, in the ancient order:

1. ♄ Saturday
2. ☉ Sunday
3. ☽ Monday
4. ♂ Tuesday
5. ☿ Wednesday
6. ♃ Thursday
7. ♀ Friday

All 168 hours, computed from the ladder: each day starts three rungs lower.

Saturday	Saturn♄	Jupiter♃	Mars♂	Sun☉	Venus♀	Mercury☿	Moon☽	Saturn♄	Jupiter♃	Mars♂	Sun☉	Venus♀	Mercury☿	Moon☽	Saturn♄	Jupiter♃	Mars♂	Sun☉	Venus♀	Mercury☿	Moon☽	Saturn♄	Jupiter♃	Mars♂
Sunday	Sun☉	Venus♀	Mercury☿	Moon☽	Saturn♄	Jupiter♃	Mars♂	Sun☉	Venus♀	Mercury☿	Moon☽	Saturn♄	Jupiter♃	Mars♂	Sun☉	Venus♀	Mercury☿	Moon☽	Saturn♄	Jupiter♃	Mars♂	Sun☉	Venus♀	Mercury☿
Monday	Moon☽	Saturn♄	Jupiter♃	Mars♂	Sun☉	Venus♀	Mercury☿	Moon☽	Saturn♄	Jupiter♃	Mars♂	Sun☉	Venus♀	Mercury☿	Moon☽	Saturn♄	Jupiter♃	Mars♂	Sun☉	Venus♀	Mercury☿	Moon☽	Saturn♄	Jupiter♃
Tuesday	Mars♂	Sun☉	Venus♀	Mercury☿	Moon☽	Saturn♄	Jupiter♃	Mars♂	Sun☉	Venus♀	Mercury☿	Moon☽	Saturn♄	Jupiter♃	Mars♂	Sun☉	Venus♀	Mercury☿	Moon☽	Saturn♄	Jupiter♃	Mars♂	Sun☉	Venus♀
Wednesday	Mercury☿	Moon☽	Saturn♄	Jupiter♃	Mars♂	Sun☉	Venus♀	Mercury☿	Moon☽	Saturn♄	Jupiter♃	Mars♂	Sun☉	Venus♀	Mercury☿	Moon☽	Saturn♄	Jupiter♃	Mars♂	Sun☉	Venus♀	Mercury☿	Moon☽	Saturn♄
Thursday	Jupiter♃	Mars♂	Sun☉	Venus♀	Mercury☿	Moon☽	Saturn♄	Jupiter♃	Mars♂	Sun☉	Venus♀	Mercury☿	Moon☽	Saturn♄	Jupiter♃	Mars♂	Sun☉	Venus♀	Mercury☿	Moon☽	Saturn♄	Jupiter♃	Mars♂	Sun☉
Friday	Venus♀	Mercury☿	Moon☽	Saturn♄	Jupiter♃	Mars♂	Sun☉	Venus♀	Mercury☿	Moon☽	Saturn♄	Jupiter♃	Mars♂	Sun☉	Venus♀	Mercury☿	Moon☽	Saturn♄	Jupiter♃	Mars♂	Sun☉	Venus♀	Mercury☿	Moon☽

The order control only relabels the display. The arithmetic stays the same: Saturday opens the ancient row, as the Pompeii graffito CIL IV 6778–6779 shows.

The mechanism is ancient, not a modern explanation. Cassius Dio describes it in Roman History 37.18–19, and Vettius Valens devotes a substantial section of his Anthologies to the planetary week, around the middle of the second century.

Sâmbătă: the kept Sabbath

Sâmbătă comes from sabbatum, the Sabbath. DEX gives lat. sambata, sl. sonbota: the word reached Romanian through Latin, possibly through Slavic. The Candrea dictionary agrees: slav. SOBOTA, from lat. SABBATUM.

Here Romanian refused the planet. In the planetary week, the seventh day belonged to Saturn, the first rung of the ladder. But Christians kept the name of the Hebrew Sabbath, and the Romanian sâmbătă is not Saturn's day.

The exact route — straight from Latin or through Slavic — stays unsettled in DEX.

The renamed day

Duminică: the Sun's day, turned the Lord's day

Duminică comes from [dies] dominica, the Lord's day. DEX gives Lat. [dies] dominica, and the Candrea dictionary calls it the only Christian name among the weekday names. Before the rename, the day was called dies solis, the day of the Sun.

No single renaming date is known. The oldest disputed attestation of kuriakē, the Lord's day, stands in Revelation 1:10. The Didache 14 mentions it, and Clement, around 190, is the first to tie the Lord's day plainly to Sunday. Constantine's own law of 321 still calls it dies solis.

The 321 law, in its own words

Emperor Constantine gave Sunday rest the force of law. Below stands the whole law, Codex Justinianus 3.12.2, with the translation beside it. Farmers are exempt, lest they miss the sowing season.

the farmers' exemption

The law is dated 3 March 321, by its subscript: pp. V non. Mart., under the consuls Crispus II and Constantine II. Some modern works write 7 March; the subscript date stays 3 March 321. The law is addressed to Helpidius.

The Latin follows the published Codex Justinianus text; the Romanian translation by Marius Comper stands in the Romanian edition of this page.

Who refused the Roman deal

The mirrors: three refusals

Not everyone kept the gods of Rome. Germanic speakers swapped four gods for their own, Slavs numbered the days instead of dedicating them to gods, and the Portuguese numbered them too, after a bishop who refused the pagan names.

Germanic speakers swapped four gods

English keeps the Sun, the Moon, and Saturn from Rome. Four days took equivalent Germanic gods, through interpretatio germanica.

For Friday, some works name Freyja instead of Frigg. The two goddesses blur easily in the sources; this page shows Frigg and notes the rival.

Slavs numbered the days

Russian dedicates the days to no god. It numbers them from Sunday: the second, the middle, the fourth, the fifth. Monday comes after Sunday, Saturday keeps the Sabbath, and Sunday is the Resurrection.

Meanings follow current Russian dictionaries and the studies cited under sources.

The Portuguese number them too

Portuguese is the only Romance language in which Monday to Friday are numbered: segunda-feira, terça-feira, quarta-feira, quinta-feira, sexta-feira. Sunday stayed domingo, and Saturday sábado. The numbering comes from the sixth century, from Martin of Braga, who refused the pagan names of the days.

Four common mistakes

1. The order of the days looks drawn by lot.

   It follows the planetary-hour arithmetic: 24 = 3×7+3. The simulator above computes it from the ladder, with no handwritten list. The Pompeii graffito, CIL IV 6778–6779, already shows the ancient row, starting with Saturday, before 79.

2. Sunday was Constantine's invention.

   Christians gathered on Sundays two centuries before the law. Justin Martyr writes around 155, in First Apology 67: “on the day called Sunday, all who live in cities or in the country gather together to one place” (Roberts-Donaldson translation). The 321 law made Sunday a civil rest day and still called it dies solis.

3. The seven-day week surely comes from Babylon.

   Not established. Babylonians had lunar schemes, with no fixed seven-day cycle. The link between planets and days is a Hellenistic astrology innovation, and the seven-day week, as a steady measure of time, is an early Roman imperial invention, from the merger of the biblical week with the planetary one.

4. Every English day carries a Norse god.

   Only four do. Sun, Moon, and Saturn stayed Roman in English; Tiw, Woden, Thor, and Frigg replaced four planets. The Germanic table above shows exactly which.

Who named your day?

Five cards, five days. Pick the right answer in each card.

Further, on the same shelf

What we do not know (and say so)

• Where the seven-day week comes from. The Babylonian hypothesis stays unproven: not established.
• When duminică took the name dominica. We hold scattered attestations, not a single date.
• Which road brought sabbatum into Romanian: straight from Latin or through Slavic. DEX gives both forms.
• Who the goddess of Friday is in English: Frigg or Freyja. The sources divide.
• What Martin of Braga decided exactly. The Portuguese numbering comes from him; the council details stay uncertain.

You speak the gods' names seven times a week. Now you know which.

Sources

Dictionaries first, then the law and the ancient texts, then the studies. Every risky claim points to its source.

Dictionaries

• luni: DEX
• marți: DEX
• miercuri: DEX
• joi: DEX
• vineri: DEX
• sâmbătă: DEX
• duminică: DEX

The law and the ancient texts

• Codex Justinianus 3.12.2, the Latin text
• Philip Schaff on the Sunday law
• Justin Martyr, First Apology 67

The planetary week

• Sacha Stern, chapter 1 (PDF)
• Cassius Dio, Roman History 37
• The planetary-hour mechanism, summarized

The mirrors

• The Germanic days (CalendarZ)
• The Slavic days (Orthodox Christian)
• Martin of Braga (Starhope)
• The Portuguese days (daysoftheweek)

Background

• dies dominica (Encyclopedia.com)
• The calendars project (UCL)

Type: Fraunces, Newsreader and Atkinson Hyperlegible, under the SIL Open Font Licence.