A history of time – the story behind our days, weeks, and months

Who do we have to thank for our divisions of time? And how did the days and months get their names? Read on to find out in our brief history of time…

We’ve been thinking a lot about time recently. It’d be fair to say that the days, weeks, and months of the past year have lost a little of their definition, with current restrictions causing the passage of time and normal routine to become a little, shall we say, distorted. Time seems more fluid (though, on some days, the speed at which it seems to move feels A LOT slower), and it reminds us that our units of measuring its passing haven’t always been in place…

Dividing the days

As with many things, we have the ancient Babylonians to thank for our 24-hour days. They were the first to divide both the day and night into 12 equal hours, later separating each hour into 60 minutes and the minutes into 60 seconds. Though these divisions of time were based on the movements of the Sun and Earth, they also had their roots in the Babylonians’ numbering system – and here’s where it gets mathematical!

An early counting method using the digits on a single hand

Unlike our standard decimal system today based around grouping numbers in ‘10s’, the Babylonians used duodecimal (base 12) and sexagesimal (base 60) numeral systems – systems that were in fact started by the Sumerians, a culture that began 2,000 years before the Babylonians, in around 4000BCE. It’s believed the system likely originated from ancient peoples using their thumbs as a pointer, and counting by using the three jointed parts on the other four fingers (try it yourself!) It was pretty logical, then, for them to divide their time using this same mathematical system.

(If you want to fall down the rabbit-hole of information on this, here’s a pretty good starting point!) 

Days become weeks, weeks become months…

When it comes to the number of days in a week, and weeks in a month, it seems we have the Babylonians to thank again. For them, the number ‘7’ held a particular significance, observing as keen astronomers, that there were seven celestial bodies in sky – the Sun, the Moon, Mercury, Venus, Mars, Jupiter and Saturn. Through their lunar calendar, which tracked the transitional phases of the moon, they also calculated that it took approximately 28 or 29 days for the moon to complete its full lunar cycle. This period (give or take a few ‘transitional’ days) became a ‘month’, and, divided into four equal parts, produced seven-day ‘weeks’.

Fragment of a Babylonian celestial calendar

Though other great civilizations chose to divide their weeks slightly differently – the Egyptians’ week was 10 days long and the Romans’ originally lasted for eight – it was the Babylonians’ system, born from such an influential culture, that lasted, spreading quickly through the neighbouring large empires of Persia and Greece.

(N.B. How the modern year came to be divided into 12 months is a more complex story, and the subject of another blog entirely! Later we’ll see that originally, the Romans chose to divide their calendar into 10 months, before necessity caused them to swap to 12)

It’s all in the name

So that’s the maths out the way, now what about the origins of the names we now use for the days and months? Unsurprisingly, the names have their roots in astronomy and the deities that were once associated with the planets. It was our old friends the Babylonians once again who set the trend, naming each day after the celestial body they believed held sway over the first hour of that day. But it’s the Romans’ adaptation of the idea which led to the days and months being named as we know them today.

History of time - Sol gives his name to Sunday

Mosaic fragment of Sol Invictus

In the ‘romance languages’, like Italian and French, the days of the week have predominantly remained very close to their original Latin forebears. If we take the Italian, starting with our equivalent of ‘Monday’: Dies Lunae, the day of the moon, became Lunedi, combining lunae (moon) and di (day); Dies Martis, the day of Mars, became Martedi; Dies Mercurii, the day of Mercury, became Mercoledi; Dies Jovis, the day of Jupiter, became Giovedi; and Dies Veneris, the day of Venus, became Venerdi. Interestingly, Dies Saturni, day of Saturn, and Dies Solis, day of the Sun, are not the root for the modern Italian sabato (Saturday) and domenica (Sunday), though they clearly influence our English versions. Instead, the pagan names for these days were replaced and influenced by the Hebrew Sabbath, day of rest, and the Latin Dominus dies, day of the Lord.

Germanic adaptations

History of time - Tyr and Tuesday

Tyr equated with Mars in an 18thC Icelandic Manuscript (ÍB 299 4)

As for our English words for the days, we’ve seen they bear traces of the Roman, but it’s a connection that’s been heavily filtered through centuries of Norse and Anglo-Saxon influences. Like the Romans before them, Germanic people also adopted the system of identifying the days with deities, this time simply replacing the Roman gods with the names of their own. Monday derives from the Old English Mōnandæg and Norse Mandag, associated with Mani the Norse goddess of the Moon; Tuesday is associated with the Norse god Tyr, a warrior god like Mars, whose name in Old English gave us Tīwesdæg; Wednesday derives from Odin’s or Wōdensdæg, like the Roman god Mercury, Odin (Anglo-Saxon Wōden) played a part in guiding souls to the realms of the dead; Thor gave his name to Torsdæg or Thursday, sharing Jupiter’s association with the sky and thunder; Frigg, the Anglo-Saxon goddess of love, gives her name to Frīgedæg or Friday; strangely, Saturday retained its Roman deity, becoming Sæturnesdæg in Old English; and finally Sunday comes from the Old English Sunnandæg, deriving from the Norse sun goddess Sunna or Sól.

As for the months…

History of time - Januarius

January from the print series ‘The Months’ by Jacobus Harrewyn. Engraving, 1698. Held in the collection of The British Museum

The months are brought to us by the Romans again, who followed a similar naming method to the days to begin with, before, it seems, losing their creative flair as they approached the end of the year. Originally the Roman calendar began with March or Martius, named for one of their favourite deities Mars. Aprilis came next, named from the Latin word aperire, meaning ‘to open’, and sacred to goddess Venus. Maius (May) and Junius (June) were named for the goddesses Maia (a deity of springtime and growth) and Juno (the goddess of marriage and childbirth). When we reach July and August though, the calendar gets a reshuffle…

As we mentioned above, originally the Roman calendar (borrowed from the Greeks) had only 10 months, and as the fifth and sixth months of the year, July and August were once known as Quintilis and Sextilis. However, under the authority of Julius Caesar in 46BCE, two additional months were added to the year, in order to better synchronise the year with the seasons and tie in with the 12 lunar cycles of the moon. These were Januarius, named after the Roman god Janus (god of doors and beginnings) and Februarius, named after an ancient festival of purification known as Februa. At first, these two months formed the end of the year, but were later moved to the beginning (which explains the odd positioning of the leap year in the modern calendar). Quintilis and Sextilis, now out of order in the calendar, were renamed Julius (July) after Caesar himself, and Augustus (you guessed it, August) after his great-nephew and Rome’s first emperor Augustus.

History of time - Roman Maias

Maias from a Roman mosaic of the months (from El Djem, Tunisia, first half of 3rd century AD) Picture Credit: Ad Meskens

And as for the rest of the months? Well, here’s where the creativity runs out. September, October, November and December are also named after the Roman numbers 7 (septem), 8 (octo), 9 (novem) and 10 (decem). After January and February were moved to the beginning of the year, these too were placed out of order numerically. Though later emperors had a go at changing the names of the months (Caligula insisted that September be renamed Germanicus, after his father, and Nero had a go at renaming April Neronium), unsurprisingly, none of these stuck, and so the original names were kept.

So, if, like us, you’re struggling with the slow passage of time and uncertainties of the year ahead, take comfort in the knowledge that January, though it may be a bleak time of year, is named for the god of gateways and new beginnings. Time will pass, and whether you’re counting in days, weeks or months, lockdown too will pass.