Like us, the Romans divided each day into 24 hours, and they assigned 12 to the daytime and 12 to the night.
These theories are now known to be infactual but they were not refuted until 1543 when the Polish astronomer Mikolaj Kopernik (a.k.a.
Nicolaus Copernicus 1473-1543) published his almost-heretical work which expounded a heliocentric or sun-centred 'solar-system'.
This effectively means that the length of the Roman hour varied according to the season, so that during the summer solstice¹ around June 21st when the period of daylight is considerably longer than the night, the twelve hours assigned to the daytime would each have to be 1 hour and 16 minutes long, while conversely, during the short days of the winter solstice around December 21st, each daylight hour would be only 44 minutes long.
There were only two days during the entire year when the Roman day contained hours of exactly 60 minutes.
It should be noted that the times of rising and setting of the Sun also varies with geographical latitude, and the data in the above table shows the length of the daylight hours at the latitude of Rome itself; this table would not be valid for many other cities in the Roman world.
Macrobius tells us that at first, the Romans used the ancient Etruscan Market Week, which consisted of seven working days followed by a market day called the Nunindae.
Ptolemy's teachings were based, in turn, on those of Plato and Pythagoras who both expounded a geocentric, 'earth-centred' view of the universe in which the sun, moon and planets all revolved about a stationary Earth, positioned as it should be, at the very hub of the cosmos.
Among the lessons published in Ptolemy's astronomical thesis Syntaxis were; "The earth does not change its position in any way whatever", also "Arguments against the earth's rotation".
Our modern calendar is closely based on that implemented by Julius Caesar during 46-45BC, and amended by Pope Gregory XIII in 1582AD.
The ancient Roman calendar was closely linked to the science of astrology and the teachings of Claudius Ptolemaeus, which were prevalent throughout the entire lifetime of Imperial Rome.
During this eighth day many public auctions were held, and Varro joked that the rural population shaved and came into the city, thus the Nunindae became a day of festivity.