Roughly 3.5 million years ago, a group of ape-like human ancestors called Australopithecus afarensis left 70 fossilized footprints in the volcanic ash of Laetoli, Tanzania. Near those remarkable footprints—discovered in 1978 by a team led by Mary Leakey—was another rare find: a clutch of fossilized bird eggs.

The eggs belonged to a francolin, a species of terrestrial guinea fowl that roosts in trees, but makes their nests on the ground. It’s impossible to prove without a time machine, but archaeologists are fairly confident that the same ancient hominins who left their footprints in Tanzania would have greedily raided a francolin nest for those delicious and nutritious eggs.

Humans have been poaching wild bird eggs since time immemorial, but the history of eating domesticated chicken eggs is much shorter. The scrambled eggs you had for breakfast would have been unrecognizable to most inhabitants of Europe before the time of Jesus. The first chickens arrived in Italy around 800 B.C., but it took many more centuries before the exotic “junglefowl” from Southeast Asia was considered edible, including its eggs.

Some of the best evidence of ancient human egg-eating can be found in South Africa. There, in sites like the Diepkloof Rock Shelter, archaeologists have identified hearths (prehistoric kitchens) dating back 60,000 years that are absolutely littered with ostrich eggshells.

Ostrich eggs, which contain the equivalent of 18 to 24 chicken eggs, were highly prized by stone-age hunter-gatherers, says archaeologist and biologist Beatrice Demarchi.

“Ostrich eggs are nutritious, clean and extremely portable,” says Demarchi. “So if you're a hunter-gatherer, you'd rather carry a few eggs with a long shelf life than drag around half a gazelle, which is a lot more difficult.”

While there was likely some danger in aggravating an ostrich, paleolithic humans clearly felt that raiding an ostrich nest was worth the risk. Whether guzzled down raw or roasted at the edge of a smoldering fire, eggs contain a nutrient-rich brew of proteins and healthy fats.

“Eggs are meant to nourish the embryonic bird until it’s developed enough to crack out of the shell and fend for itself,” says food scientist and author Harold McGee. “So it has to have everything necessary for making a bird. Eggs have plenty of protein, and all the materials needed to make cell membranes and provide energy for the transformational processes that take place between fertilization and hatching. It’s an amazing package.”

In addition to their life-saving nutritional content, ostrich eggs had many “post-consumption” uses for paleolithic people. An emptied ostrich egg was the perfect canteen for carrying water, and ancient artists reused the super-hard ostrich shell as a canvas for some of the earliest human artwork.

Australia was one of the last places on Earth that ancient humans reached and settled. When the first people arrived there around 60,000 years ago, Australia was home to several species of oversized “megafauna,” including a large emu-like bird called the Genyornis.

The flightless Genyornis stood 7 feet tall, weighed over 500 pounds and laid some equally impressive eggs. Demarchi says that according to the archeological record, the first humans in Australia weren’t hunters, but they actively raided Genyornis nests for those big, nutritious eggs.

Archaeologists in Australia have found fragments of Genyornis eggs with telltale burn marks that are consistent with careful roasting on a fire, not a natural wildfire. As with several other Ice Age megafauna, the Genyornis was driven to extinction within a few thousand years of human contact. Did the first Australians’ taste for eggs wipe out the Genyornis?

“The fact that you suddenly have the appearance of these burning marks after people got there, and then the eggshells disappear entirely from the archeological record around 47,000 years ago, it’s a pretty strong indication,” says Demarchi.

It’s no secret that the modern chicken (Gallus gallus domesticus) is a direct descendent of the red junglefowl (Gallus gallus), a wild bird native to Southeast Asia. But until recently, scientists weren’t sure when and how the red junglefowl was first domesticated.

Julia Best is a zooarchaeologist, which means that she analyzes ancient animal remains for clues about human-animal interactions in the past. Best is particularly interested in birds, including the now-ubiquitous chicken.

Putting a confident date on chicken domestication is a challenge—chickens could have descended from several junglefowl species—but Best and her colleagues were able to rule out the really early dates using radiocarbon dating and careful zooarchaeological analysis.

“There have been studies that suggested chicken domestication happened as far back as 10,000 years ago in China, but those turned out to be pheasant bones,” says Best. “It’s much more likely that domestication happened around 3,500 years ago (1500 B.C.) in Southeast Asia.”

The earliest unambiguous chicken bones identified by Best and her team were found at a Neolithic site called Ban Non Wat in central Thailand. It looks like agriculture was the key that unlocked chicken domestication. The bird bones at Ban Non Wat correspond with the advent of rice farming in Thailand. That tasty new food source may have brought humans and tree-dwelling junglefowl into closer contact.

“That shared food resource would have tempted the red junglefowl down from the trees and into the areas that humans were cultivating,” says Best, “which would start to break down that wild boundary.”

Once the red junglefowl were tamed, humans likely discovered the bird’s handy biological trick. Unlike some other bird species, which only lay eggs once a year in the spring, red junglefowl can lay multiple times, producing between two to four clutches a year. And if their first clutch of eggs is stolen, they can quickly re-lay to replace them.

Best points out that those first domesticated junglefowl were nothing like modern laying hens, which are egg-producing machines. But 1500 B.C. is now our best guess for when and how the human-chicken-egg relationship began.

It took more than 500 years for chickens to make their way to Europe. The eye-catching, red-feathered birds from Southeast Asia were transported along Greek, Etruscan and Phoenician trade routes and first arrived in Greece and Italy around 900 B.C.

What’s surprising, says Best, is that for centuries after the chicken’s introduction to Europe, nobody even thought about eating them.

“There seems to be a time lag of around 400 to 500 years in some locations between chickens arriving and then really being considered food,” says Best. “Instead, chickens seem to be treated as a special animal. Maybe it's because they're exotic and they've come from a distant land. I mean, if you'd never seen a chicken before, imagine how weird it would be.”

Best says that chickens may have also been important for social status and religion. The earliest chicken bones in Italy were found in tombs and cultic locations. In the ancient world, birds like cranes and crows were often buried with the dead to bear their souls to the afterlife. Chickens, too.

It wasn’t until around 500 B.C. that the Etruscan civilization in Italy first developed a taste for chickens and their eggs. Some of the earliest evidence of chicken eggs being eaten in Europe comes from a small hilltop town in Tuscany.

San Casciano dei Bagni is home to thermal baths that were a pilgrimage destination as far back as the 3rd century B.C. Visitors would leave offerings for the gods in exchange for a dip in the healing waters.

Archaeologists excavating the thermal baths at San Casciano have recovered impressive bronze statues, countless gold coins and thousands of eggshell fragments. In addition to eating the chicken eggs, it appears that some visitors tossed whole eggs into the baths, a nutritious treat worthy of the gods.

Each time the chicken arrived in a new location—like Northern Europe and the British Isles—it was greeted as an exotic specimen, not a source of food. When Julius Caesar invaded France and Britain during the Gallic Wars (58 to 50 B.C.), he wrote this about the Britons: “They do not regard it lawful to eat the hare, and the cock, and the goose; they, however, breed them for amusement and pleasure.”

Caesar must have found the British abstention from chicken strange, because the Romans were actively gobbling down both chickens and their eggs.

“Ancient Romans ate many types of eggs: chicken eggs, duck eggs, partridge, goose, quail, pheasant, ostrich, crane, pigeon, and the most prized of all, peacock eggs,” says Almudena Villegas, a food historian and author. “Eggs were a common ingredient in the Roman diet and Roman markets had specialized egg sellers called oviarii.”

As the Roman Empire spread, so did the Roman diet, including a taste for eggs. The first clear evidence of egg-eating in Britain was limited to “Romanized” sites like military outposts, urban settings and amphitheatres, says Best.

At the Chester Amphitheatre in England, which dates from the first century A.D., archaeologists discovered loads of chicken eggshell fragments buried in the soil under the seats. Apparently, when people in Britain watched sporting events like gladiatorial combat and wrestling, they snacked on hard-boiled eggs, a Roman treat.

“We have frescoes and other images of market stalls selling food outside of amphitheatres, just like we might get a meat pie at a football match today,” says Best.

Beyond those Romanized sites, chickens and their eggs didn’t become a regular part of the British diet until the third century A.D.

Breakfast wasn’t really a “thing” in Roman times, says Villegas. The first meal of the day, known as ientaculum, usually consisted of some cold leftovers from the night before (a little bread or meat) or simply a restorative shot of watered-down wine.

Instead of eating eggs for breakfast, eggs were deployed in a wide variety of sweet and savory Roman dishes. The ancient text De re coquinaria (“On the Subject of Cooking”) by the Roman writer Apicius contains nearly 500 popular Roman recipes, including eggy custards, quiches and omelettes. (The word “omelette,” McGee suspects, can be traced back to the Latin word lamella for a thin metal plate.)

Romans of all classes enjoyed ova spongia ex lacte (egg sponge with milk), a savory-sweet omelette made with eggs, milk, honey and pepper. Wealthier Roman households prepared a show-stopping savory custard called a patina, a mix of eggs, milk, meat or fish heated in the oven until it congealed into a flan-like consistency.

“They used these wonderful decorative molds—we’ve found them in Pompeii and Rome—in the form of a fish or a hunting scene,” says Villegas. “So the patina custard would come out in the form of the mold. They’re beautiful. The Romans sought out beauty in their food, just like we do.”

Early on, ancient cooks discovered some of the magical properties of eggs when mixed with other ingredients.

“Eggs contain amazing structural materials,” says McGee. “The white is mostly protein—you heat it and it forms a solid. The yolk is a really complex combination of proteins and fats. It’s a preexisting emulsion. When you separate these materials and mix them with other liquids (water and fat), the egg becomes even more versatile.”

Mayonnaise, for example, is a classic egg-based emulsion. Egg yolks are whisked together with olive oil and a touch of vinegar to form a thick, creamy sauce. Most food historians credit the French with inventing mayonnaise in the 18th century, but Villegas believes that the Romans were eating it 1,000 years earlier.

She found a recipe in the same 5th-century cookbook by Apicius for a sauce in which olive oil is mixed “drop by drop” into a bowl of soft-boiled eggs until they are “made into one.” The Romans didn’t have whisks or even forks, but Villegas and a professional chef successfully recreated the sauce using a small wooden brush. No word yet from the French.

Meringues and soufflés are made by whipping egg whites until they become stiff, another technique known to ancient cooks, says Villegas. In a fifth-century text called De observatione ciborum (“On the Observance of Foods”), the Byzantine Greek physician Anthimus describes egg whites whipped to a “foam” and baked into “spheres of snow,” perhaps the first meringue.

“The year-round availability of eggs is very much a modern invention,” says McGee. “It requires keeping chickens in a controlled environment, so they don’t know about day length. The reason we have Easter eggs is that the springtime was when birds were laying eggs like crazy. You would end up with many more than you could possibly eat at that moment, so you found ways to preserve them and use them up as much as possible.”

Pickled eggs were a popular snack in ancient Roman taverns, but arguably the most famous (infamous, really) preserved eggs are the so-called “century eggs” of China. The recipe for century eggs, known as pidan, dates to the Ming dynasty (1368-1644) in China, where legend says that a teahouse owner discovered a clutch of duck eggs laid in wood ash.

Century eggs are made by coating a whole, uncooked egg with a strongly alkaline paste of wood ash (or lye), salt and mud. The typical century egg is cured for a few weeks or months, but the finished egg’s curious appearance (and odor) has convinced countless tourists that the pungent delicacies have been pickling for at least 100 years.

“They’re really…different,” says McGee, who describes a century egg’s smell as sulphur overlaid with ammonia. “The white of the egg becomes hard and translucent brown, kind of like an aspic. The yolk is also coagulated, but in a soft way, and it’s kind of greenish. The whole thing has a very powerful aroma.”

The next time you balk at the price of a dozen eggs, be grateful that you didn’t have to outrun an angry ostrich or personally domesticate a wild bird in order to enjoy a delicious omelette. Egg eating has never been so easy.