But one academic, an expert in the study of DNA, has found it was something far simpler - a humble bowl of porridge.
Alistair Moffat, who has studied the development of early humans through his research into DNA markers, has argued the move of hunter-gatherer societies into farming was pivotal to the building of nations.
Speaking at the Chalke Valley History Festival, he said the "greatest revolution in our history" came from the development of farming, which in turn brought porridge.
Before porridge, he claimed, women were compelled to breast feed their children until the age of four or five years, because fragile milk teeth could not cope with the meat and vegetation enjoyed by hunter-gatherers.
The action of breast feeding, a natural contraceptive, as well as the necessity of carrying babies around as they moved, meant women often had long intervals between giving birth.
Mr Moffat, whose next book is entitled "The British: A Genetic Journey", claimed feeding children porridge left women free to have more children, who then went on to populate the Earth.
Speaking at the Chalke Valley Festival this week, he told an audience: "This is true.
"The greatest revolution of our history wasn't the invention of the iPad, it wasn't the invention of the steam engine, it wasn't all the things you might might lay your mind to.
"The great invention, the greatest revolution in our history was the invention of farming. Farming changed the world because of the invention of porridge."
Mr Moffat, whose company Britain's DNA recently found Prince William had Indian ancestry, added: "Hunter-gatherer bands were mobile, they had to be because they ended to move between ranges.
"And they could not carry infants - more than one infant - around with them at a time. Imagine North American Indians with a papoose.
"It couldn't be the case that hunter-gatherer bands had lots of children at the one time.
"They ensured that this could not be the case in one particular manner; nursing. Breast-feeding makes it very difficult for a woman to conceive.
"In hunter-gatherer societies, infants were breast fed for much much longer until the age or four or five years old. The reason for that is that mother's milk was their sole source of class one protein, because of the softness of their teeth.
"Their teeth simply could not cope with the roots, fruits and berries and so on that we're the staple of the hunter-gatherer diet.
"When farming was invented and cereals were grown, charred, ripened and mashed into a pulp - porridge - it could be spooned into the mouths of infants and was extremely nourishing. And it allowed women to stop breast feeding after one or two years and so the birth interval halved and the population rocketed.
"Farming also involved not mobility but stability; the ability to nurture land and make it production, to look after your domesticated animals and so on. And as populations expanded they had to move. All of these surplus children had to move.
"And you watch a particular chromosome marker rippling across Europe at this time."
Furness, Hannah. 2013. “How a bowl of porridge transformed mankind”. The Telegraph. Posted: June 28, 2013. Available online: http://www.telegraph.co.uk/science/science-news/10148594/How-a-bowl-of-porridge-transformed-mankind.html