Sum of us: The ancient and modern history of counting people

The earliest reasons for counting people, as tribal settlements grew into some of the earliest cities, involved food stocks. How many people were there, how much food was being produced, and how much was needed, were the questions that needed to be answered.

Counting stores also helped estimate how much would be paid in taxes and levies, which were used to support the rulers and feed their armies. And counting men (through most of history, censuses have focused on men) created a record of how many were available, if needed, for campaigns of either attack or defence.

Even today, these are core functions of population-level data. The data also now shapes international relations and domestic policymaking, market dynamics, resource and funds allocations, and serves as an ongoing historical record of countries, faiths and communities.

The ancient civilisations of Persia, Egypt, India and Rome all conducted population surveys, with some of the methods they used and data they collected passing into history through travellers’ accounts, administrators’ accounts, inscriptions and religious texts. The Bible, for instance, mentions that Mary and Joseph of Nazareth were on their way to record their names in such an exercise, when Jesus was born in a manger.

The Sanskrit treatise Arthashastra by Chanakya mentions censuses being conducted in the Mauryan Empire (321 BCE to 185 BCE), and proposes detailed methods of collecting records of age, occupation, income, expenditure patterns and land use.

The word “census” itself has its roots in the Latin “censere”, meaning estimate. Its earliest recorded use dates to the Roman Empire, which conducted methodical surveys every five years, between 27 BCE and 286 CE, to keep track of citizens and land holdings, employment, social class and privileges, and to calculate existing and potential troop strength.

Their records were preserved meticulously on papyri, but, sadly, don’t offer a complete picture. Married women and children often weren’t registered at all. Single women and orphans sometimes made it to a separate list, represented by their guardians. But most of the surveys accounted only for the men.

So serious was the Roman empire about tracking the men and their assets, however, that not attending a census gathering was viewed as a form of treason and was punishable by imprisonment, enslavement, or death.

Han China, Inca knots and a Domesday Book

That global tally would rise to about 300 million by 1 CE, according to the US-based non-profit research and data organisation Population Reference Bureau.

Fast-forward about 1,000 years and we have a dramatic instance in which a census caused widespread panic. In 1086, King William I (or William the Conqueror) ordered commissioners to spread out across every county in his kingdom (modern-day England and parts of Wales), to collect information on the number of people, land ownership and estimated land values, with an eye on the dues owed to him. The records formed at this time sealed the fates of many estates, merchants, tradesmen and families, and came to be called the Domesday Book (Middle English for doomsday). The data was actually compiled as a book, one that’s now preserved at the National Archives in London.

Not all records were written. The 15th century Incas left behind colourful knots on string. These cord systems called quipu worked like abacuses, with different knots representing tax dues, military arrangements and population figures. The grand but short-lived Inca empire (which only endured for a few hundred years) had an estimated population of 10 to 12 million at its peak.

Around this time, between the 15th and 17th centuries, the estimated global population crossed 500 million. Figures vary because, in the absence of comprehensive records, they are based on estimated growth rates for each period.

Quebec, Iceland, India

In the modern era, colonial powers such as England, France and Denmark used censuses to monitor and control their colonies. The idea of using such statistics as a means of gathering information to understand and develop society dates to only the 17th century.

According to UNESCO’s Memory of the World (MoW) Register, early efforts at a standardised count can be traced to a small but well-designed survey conducted in New France, now Quebec, in 1666. It went door to door, and counted 3,200 French citizens in the Canadian region.

The 1703 census of Iceland is the oldest existing one to include every member of a country, along with details such as name, age and social status, says the MoW register. It reported that the country’s population stood at 50,366 individuals.

In 1790, the US government officially authorised the act of census-taking every 10 years, sending marshals out on horseback to ask six questions: names of the white, male householder; names of all free white males above 16; free white males under 16; free white females; all other free persons and slaves. Slaves, notoriously, counted as three-fifths of a person; native Americans were not counted at all, until 1860.

England’s first standardised census, meanwhile, had a lot to do with hunger. Years of poor harvests and wars with France meant that bread imports were affected in 1800. With just vague estimates available from church registries, of how many needed to be fed, the Census Act was passed. By 1801, parliamentary officer and statistician John Rickman had completed the first modern survey of the population of England and Wales, which included women and children but not members of the military, prisoners, or those at sea.

Thus counted, the tally was found to be 8.9 million. Around this time, in 1804, according to the United Nations Population Division (UNPD), the global tally of humans crossed 1 billion.

In British India, periodic population surveys were conducted sporadically, from 1872 on. The first such survey in independent India was undertaken in 1951.

In 1958, the United Nations’ Statistical Commission issued a set of guidelines for population and housing surveys around the world. Two years later, UNPD reports, the global tally crossed 3 billion.

On November 15, 2022, global population estimates crossed the 8 billion mark.

Counting people remains a difficult task. Click here to read the Wknd story on people identifying as Jedi knights in censuses around the world.