How the Ancients Shaped the Week

The seven-day week has endured for thousands of years, surviving empires, revolutions, religious shifts, and even a few determined attempts to replace it. Its origins lie in a mix of astronomy, astrology, religion, and ancient practicality — with a healthy dose of historical debate.

Many historians trace the roots of the seven-day week to ancient Mesopotamia, home to some of the world’s earliest astronomers. The Babylonians closely observed the sky and attached special importance to the number seven, partly because they recognized seven major celestial bodies moving independently: the sun, the moon, Mercury, Venus, Mars, Jupiter, and Saturn. Today, we know the sun and moon aren’t planets, but in the ancient world they were grouped together with the five planets visible to the naked eye. 

The Babylonians also used a lunar calendar, and the phases of the moon may have helped shape the structure of the week. A full lunar cycle lasts about 29.5 days, which can be divided into four roughly seven-day phases. Some scholars believe Mesopotamian societies, including the Sumerians and Babylonians, used these quarter-moon intervals as the basis for a recurring seven-day cycle, and this is one basis for our current week.

However, scholars continue to debate exactly how much the modern week is influenced by this Babylonian practice versus by ancient Jewish tradition. The biblical creation story helped cement the importance of the number seven in Jewish culture: According to Genesis, God created the world in six days and rested on the seventh. That seventh day became the Sabbath, a recurring day of rest and worship. Unlike many earlier calendars tied directly to lunar phases, the Jewish week evolved into a continuous repeating cycle independent of the moon.

The Romans initially followed a different system entirely. For centuries, Roman civil life revolved around an eight-day market cycle. But as astrology from the eastern Mediterranean spread through the Roman Empire, the seven-day planetary week became increasingly popular. Each day was associated with one of the seven classical planets.

How We Got to Seven Days

In 321 CE, Roman Emperor Constantine officially established the seven-day week in the Roman calendar, helping spread it across Europe. Some of those planetary names still survive in English today. Sunday honors the sun, Monday the moon, and Saturday Saturn. The names for the other weekdays reflect Anglo-Saxon names for Norse deities. Tuesday comes from Tiw, a Norse war god linked with Mars. Wednesday honors Odin (or Woden), associated with Mercury. Thursday derives from Thor, connected with Jupiter, while Friday honors Frigg, tied to Venus.

Not every culture embraced seven-day weeks, however. Ancient Egypt sometimes used 10-day cycles, while parts of West Africa followed four-day market weeks. Revolutionary governments also occasionally tried to reinvent the calendar. During the French Revolution, reformers introduced a 10-day week intended to break with religious tradition and make timekeeping more “rational.” (All the days and months were named after elements in nature.) Soviet officials later experimented with five-day and six-day workweeks in an effort to maximize industrial productivity; the days were even color-coded. Neither experiment lasted.

The persistence of the seven-day week is remarkable, considering how arbitrary the unit really is. Unlike days, months, or years, a week is fundamentally a human invention — one shaped by ancient sky-watchers and thousands of years of habit.

The Roman Workday Ended at Noon

The ancient Romans didn’t have clocks they could use to count the hours of the day. Instead, they kept track of the time using the position of the sun, and employed devices such as sundials to divide the day and night into 12 evenly spaced units called “hora” (hours). Since tracking the sun was the Roman citizen’s principal timekeeping method, the workday was structured around solar positions that were easy to measure with the naked eye, such as sunrise, noon, and sunset. For this reason, a typical citizen would usually start their workday at dawn, which marked the first “hora” of the day, and stop working at noon. This left the rest of the afternoon open for leisure, and citizens from all levels of Roman society would spend that time attending sporting events, theatrical performances, and the all-important public baths.

The Roman People Loved to Gamble

A love of gambling extended to all levels of ancient Roman society. Less-wealthy citizens would place bets on a wide variety of board games and dice games, which they played in taverns, city streets, and other public spaces, while the rich would build private gaming rooms in their homes. Romans would also frequently bet on the outcomes of gladiator fights and chariot races. (For the most part, only men were permitted to gamble, though women were allowed to participate in games of chance during special festivals.) Even the Roman emperors got in on the action. Rulers such as Augustus and Nero were known for their gaming habits, and for betting small fortunes on a single throw of the dice. Roman Emperor Claudius even had a custom-made carriage built with a gaming table so that he could gamble while traveling.

The Roman Forum Was the Center of Public Life

With its location right in the middle of the city, the Roman Forum was quite literally the center of everyday life in ancient times. It was where the typical Roman citizen could shop, talk, and find entertainment. It was also the site of most of the city’s public gatherings, the Roman courts of law, and the meeting place of the Roman Senate. What’s more, the forum housed some of Rome’s most important religious sites, including multiple temples dedicated to Roman deities. In other words, if you were a Roman citizen, chances were good that you’d be making frequent visits to the forum for everything from daily errands to grand citywide ceremonies.

There Was a Temple Where Citizens Could Go to Worship Caesar

One prominent temple in the Roman Forum was dedicated not to the worship of a mythological god, but to the former dictator of Rome, Julius Caesar. During the funeral games held in Caesar’s honor shortly after his assassination in 44 BCE, a comet appeared in the sky for seven days, which the Roman populace interpreted as a divine omen that Caesar’s soul had ascended to the status of divinity. This popular belief that Caesar had become a god was codified into law two years later in 42 BCE, when the Roman Senate officially declared him a deity. After this, a temple was built in the forum in Caesar’s honor. It even had an altar where Roman citizens would offer sacrifices to the deified leader, just as they would to supernatural Roman gods such as Jupiter and Saturn.

An Alternative Theory

Historical sources are vague when it comes to the tersorium — it seems that few Romans found it noteworthy enough to warrant a weighty text or treatise. This has caused some modern scholars to question the actual purpose of the tool. We know it was found in most public latrines, but was it used for the cleaning of numerous behinds or simply for scrubbing the latrine itself, much like a modern toilet brush? 

The greatest proponent of the latter theory is Austrian archaeologist Gilbert Wiplinger. He argues that the popular idea that Romans used the tersorium to clean their behinds is incorrect. Having reviewed ancient textual sources, including Seneca and Martial, he notes that none of them clearly describes the sponge-on-a-stick being used for personal hygiene, and that a more logical — not to mention less gross — explanation would be its use as a toilet brush.

So if the Romans didn’t clean themselves with the tersorium, what did they use? Having examined scraps of cloth in an ancient septic tank in Herculaneum (an ancient city preserved in Campania, Italy), environmental archaeologist Mark Robinson concluded that fabric scraps were likely used instead of a sponge. Another option was to use pottery shards, known as pessoi (Greek for “pebbles”). This may sound almost as bad as using a shared sponge, but these pottery pieces — which were readily available in ancient Rome — were specially selected, with smooth edges. 

The Romans likely had options when it came to bathroom hygiene — but whether that was in the form of a shared sponge-on-a-stick, scraps of fabric, shards of pottery, or a combination of all three (or more), it’s hard to know for certain. What we can say for sure is this: We should all be very grateful for toilet rolls and bidets.  

Armenia Was the First Country to Adopt Christianity as an Official Religion

Though modern-day Armenia did not achieve lasting independence until 1991, the country’s origins date back to around the year 2492 BCE according to Armenian mythology. In that year, an ancient Armenian warrior known as Hayk is believed to have defeated invading forces led by a Mesopotamia leader called Bel, which in turn saw what now encompasses modern-day Armenia fall under Hayk’s dominion. Many centuries later, Armenia made history by becoming the first country to adopt Christianity as its official state religion. Around the year 300 CE, an apostle named St. Gregory the Illuminator converted King Tiridates III of Armenia to Christianity, and it was made the official state religion in 301 CE. The newly formed Armenian Apostolic Church subverted the pagan ideology that once existed throughout the region, and it eventually became the country’s national church.

The First Recorded War Took Place in Present-Day Iran

The ancient kingdom of Elam, located in the southern region of modern-day Iran, contained settlements dating as far back as 7200 BCE. Millennia later, around the year 3200 BCE, the Proto-Elamite period began, marking the start of organized civilization throughout the region. Though few specifics are known about these early societies, what is known is that the region was the site of the first recorded war in human history. Around 2700 BCE, the Sumerian King Enmebaragesi led an attack against the Elamites, ultimately emerging victorious. Though there may have been conflicts before this, the battle — for which details are sparse — marks the earliest recorded account of a long-distance military campaign between opposing independent states.

The Oldest Surviving Anatomical Atlas Originated in China

In 1973, a seminal 2,200-year-old atlas of human anatomy written on ancient silk was discovered in south-central China, dating to the time of the Han dynasty (206 BCE to 220 CE) — making it the oldest surviving anatomical atlas ever discovered. Known as the Mawangdui medical manuscripts, these texts describe various “meridians” found throughout the human body, a term used to refer to arteries, blood vessels, and other internal elements. The Mawangdui texts also predate many other ancient Chinese texts related to acupuncture, suggesting that these early anatomical findings may have heavily influenced the science of acupuncture in the region. The artifact was uncovered in the tomb of a Han dynasty aristocrat named Xin Zhui (also known as Lady Dai), who was buried alongside copies of the medical texts in 168 BCE.