Britain saw centuries of economic growth under Roman rule

After the Romans conquered Britain in AD 43, the technologies and laws they introduced led to centuries of economic growth of a kind once thought to be limited to modern industrial societies. That is the conclusion of an analysis of thousands of archaeological finds from this time.

“Over that period of about 350 years, you’re looking at roughly a two and a half [fold] increase in productivity per capita,” says Rob Wiseman at the University of Cambridge.

It has long been believed that economic growth in the ancient world depended on having more people and more resources, says Wiseman: to increase food production, say, required more land and more farm workers. This kind of growth is known as extensive growth.

By contrast, economic growth today is driven mainly by increased productivity, or intensive growth. Thanks to mechanisation and better breeds of plants and animals, for instance, more food can be produced from the same area of land with fewer workers.

Some recent studies have challenged the idea that intensive growth occurred only after the industrial age began, inspiring Wiseman and his colleagues to look at growth in Roman Britain from AD 43 to 400.

The team’s research was made possible by UK laws requiring archaeological investigations to be done when a site is developed, says Wiseman. “The result is there’s been tens of thousands of archaeological excavations done in this country. And, moreover, that data is publicly accessible.”

By looking at how the number of buildings changed over time, the researchers were able to get an idea of how the population of Roman Britain grew. There is a strong relation between the number of buildings and population size, says Wiseman.

To get an idea of economic growth, the team looked at three measures. One was the size of buildings, rather than the number of them. As people grow richer, they build bigger houses, says Wiseman.

Another measure was the number of lost coins found in digs. “These are things that have fallen through the floorboards, or they’ve been lost in the baths, or something like that,” he says.

The idea is that the more coins are in circulation, the more are likely to be lost. The team didn’t count hidden hoards of coins, as these reflect instability rather than growth.

The third measure was the proportion of crude pottery, such as cooking pots and storage pots, to more ornate pottery like decorated plates. Economic growth requires people to interact more and socialise more, which means “showing off” when guests are present, says Wiseman.

Based on these measures, the team found that economic growth exceeded that expected from population growth alone. They estimate that per capita growth was around 0.5 per cent between AD 150 and 250, slowing to around 0.3 per cent between AD 250 and 400.

“What we’re able to show is yes, after the Romans arrived, there was definitely intensive growth,” says Wiseman. The pace of growth rather than the kind of growth is what probably distinguishes the modern world from the ancient one, he says.

The researchers think that this growth was driven by factors such as the roads and ports built by the Romans, the laws they introduced making trading safer, and their technologies, such as more advanced grain mills and better breeds of animals for ploughing.

The higher growth between AD 150 and 250 may be a result of Britain catching up with the rest of the Roman world, says Wiseman. “You’re moving from a small tribal society where there’s not a lot of interaction going on to a world-spanning economy.”

What isn’t clear is whether this economic development made people happier or healthier. “Just because the productivity is going up doesn’t automatically mean that the welfare of Britons who were invaded and colonised was better under Rome,” says Wiseman. “That’s an open question.”

To investigate this, the researchers now plan to look at human remains to work out things such as how long people lived.

“I am convinced that they are right and that, indeed, intensive growth took place in Roman Britain,” says Alain Bresson at the University of Chicago, Illinois.

“A lot of archaeologists have noted compelling evidence for economic growth in Roman Britain, but this paper adds a welcome formal theoretical dimension to the discussion,” says Ian Morris at Stanford University, California.

However, Morris suspects that the lower average growth rate from AD 250 to 400 actually reflects high growth followed by rapid decline as the Roman empire began to break up. Further studies will resolve this, he says.