Feature: How do we know the past? Archeologists explain their vital role

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Ground-penetrating radar, underwater diving and bio-skeletal remains are just the top layer of their relentless dig into history.

The borders of the great Persian Empire once extended from the Mediterranean to the Indus River in modern Pakistan. China’s first emperor built an army of clay warriors to protect him in the afterlife. The Mesopotamian code of Urukagina is the oldest known set of laws in the world.

We often take such facts of history as givens: things that were always true and seemingly always known. But the past isn’t settled territory. It is a faraway country, constantly being discovered and investigated by people specially trained to interpret it.

Archeologists play a vital role in corroborating and refuting what history’s writers have told us. In this way it serves as one of the major avenues for knowing the past. But how do archeologists collect their information? How do they know who, what and when? Where do they get the facts?

An excavation site near the Sea of Galilee. Image: Gonen Sharon.

An excavation site near the Sea of Galilee. Image: Gonen Sharon.

For starters, you need to know where to look, said Jon Frey, a Michigan State University professor and expert in Greco-Roman art.

“And sometimes even your best guesses come up short,” he said. “It’s one of the most exciting things about archeology actually.

“Sometimes we’ve always known where things are. In my own experience, things like the Acropolis in Athens, ever since it became an important site in the Bronze Age, it’s always been known and occupied. So archeologists simply peel back the many layers of occupation, use and re-use of that site to get at the earlier origins.”

In cases where you don’t know where something is, there is the advantage of written documents. People who wrote histories, poems or Greek tragedies make reference to certain characters, towns and monuments. There are some writers who are important because they were like ancient hitchhikers who journaled about the places they visited.

If those don’t help, archeologists sometimes do a survey where they simply walk through the countryside and look for things on the surface – the “signs” of the past.

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Magnets are used to look beneath the surface for signs of artifacts. Image: Tapatio.

“It’s strange but most of the time what’s buried beneath the soil makes its way up to the surface a bit, through plowing, human activity or even animal activity,” Frey said. “You’ll be walking and see nothing, nothing, nothing until you see there’s fairly large concentrations of pottery, pieces of building that might become a site.”

In recent decades, archeologists have been using more technological methods, said Lisa Nevett, a University of Michigan researcher and classical archeologist, such as ground-penetrating radar. Techniques measure the electrical resistance of different substances underground and multispectral imagery is also used from satellites to see through vegetation and reveal the features of the earth.

“In decades past, they would fly over in planes and often notice that shrubs would grow differently on top of buried structures,” Frey said. “They would see plants wouldn’t grow or wouldn’t grow as tall. You can see amazing patterns of city streets and houses that were built in ages past. People are now using Google Earth for that!”

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NASA satellite imagery of Naqsh-e Rostam, which holds the ancient tombs of Persian kings. Image: Pentocelo.

Often, knowing where to look for the facts of the past involves the people of the present.

“Simply talking to and becoming familiar with the people who are actually living in the area is one of our most powerful tools,” he added. “These are the people who are going out every day farming their land or taking care of their lawn. Coming to a fair understanding with them can be very productive for understanding where things might be.”

Raven Garvey, a hunter-gatherer specialist also at Michigan, agreed: “In archeology’s past, farmers or tillers of land would often be the ones to come up and tell an archeologist what they’ve found.”

Finding the material is one thing, she said. How to interpret it is another. Because ancient societies have many complex parts, the field has evolved to the point where it relies more and more on whole teams in order to understand what things mean.

When the field was young, it was often the case that one person was the expert in everything: the particular language, the interpretation of mosaics, the pottery, biology and history of an area, Nevett said. “They would study for years and then publish all of their findings in big volumes about the site. Now it has become so specialized that teams of people need to come together for the project to work as a whole.”

Jon Frey conducting a 3D laser scan survey on the island of Crete in Greece. Image: Susannah Van Horn.

Jon Frey conducting a 3D laser scan survey on the island of Crete in Greece. Image: Susannah Van Horn.

The type of specialists you’ll see often depends on where you are and what you need.

“It can depend on environment,” Frey said. “If you’re working on a site that’s in a cave, you’ll need experts in geology and subterranean environments. If you’re working in an urban setting, you’ll need a specialist in architecture who can interpret things like plaster and paintings. For an underwater setting like a shipwreck, you’ll need teams of divers and conservators trained to preserve things that are soaked with salt water.”

Depending on the artifacts you find, you might need a coin specialist. If you’re excavating graves you might need a bioarcheologist – somebody who can study human remains and make sure that they stay around for the future. Some can chemically study bones to see what these people used to eat, Garvey said.

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Archeologists also take comprehensive notes so that future scholars can go back, imagine every detail of the scene and make their own inferences. Image: Dennis Jarvis.

Once archeologists, field managers, volunteer diggers and assorted specialists acquire artifacts, a big part of their job is making sure each finding is described in a level of detail that’s “almost absurd,” Frey said.

“When an archeologist finds something and they can’t explain it, they ‘ll say I found this thing here, in this location, found next to these types of things, dating back to this point in time. Has anyone seen anything that looks like this?’ he said.

“A year or two later, another archeologist will contact the first and say, ‘I’ve found something very similar and found it in similar context. I found a description in a historical document that says this item was used for this or that. We’re all collectively helping each other to better understand the stuff we’re finding.”

It’s a necessity Nevett understands very well. She’s entering a new project designed to rediscover an older site which another digging team excavated in the early 20th century. That team did relatively little to describe what they found and didn’t keep many artifacts.

“Like most sciences, they didn’t have the modern, more careful techniques we have now,” said Garvey.

Such meticulous description plays a central role in divining what artifacts were used for and what ancient life may have been like.

“One of the most important concepts for interpreting objects from the past is context,” said Frey. “Where did you find it?

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It’s especially important that objects are documented where they are. Disturbing their location can upend its relationship with other objects, and can disturb the interpretation of those objects as well. Image: Apdency, Wikimedia Commons.

“This is why archeologists get really bent out of shape when someone walks up to them and asks, ‘What is this?’ It can be like taking something from a crime scene. Was the pot in the front room or back room? What were the things it was next to? These facts can tell us whether it was for daily use or a luxury item, for cooking or for storage, etc.”

When Nevett researched relationships of men and women in Greco-Roman households, she made especially sure to take note of the spatial relationships between objects. The prevailing wisdom – gained from a small number of ancient texts – was that men and women lived in a divided house, living relatively separate home lives. But based on the make-up of how houses were structured, and the mix of items traditionally belonging to women and men, her physical evidence showed that their home lives were actually quite integrated.

It’s a great example of what archeology can provide to history. It can back it up, challenge it or add context to it, she said.

An added challenge, however, is trying to tell the difference between garbage and continuously used objects. If you look at run-down or poor areas in the United States today, you’ll see people throw the garbage they have into the abandoned buildings, Nevett said. It’s something you see in places that have lost lots of population, like Detroit. It often happens when ancient cites are depopulated.

Or, Frey said, a lot of things are missing because they’ve been used for other purposes.

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Frey conducts a survey of a Byzantine wall at the site of Sparta in Greece. Image: Jean Li.

“Where I work, in Greece, you can still today go into the countryside and see old country houses built in the 1800s where the builders scavenged around and used pieces of ancient monuments as building materials,” he said. “It was a common practice throughout the Middle Ages that if you found a bronze statute, armor or iron, the present need of people was for the metal, not for the artifact.

“Quite often those things get melted down and turned into something else. The vast majority of bronze statues from the ancient world got melted down and made into nails, spikes, spears and stuff like that. Things continue to be used all the time until they reach the end of their use life, and that stuff is often what we find.”

Though the challenges are many, archeologists are still discovering more and more. And by continuing to add new tools and new information, we’ll continue to get a more holistic picture of that county called the past.

Bit by bit, dig by dig.

Featured Image: Jon Frey leading a group of students on a study abroad to Greece. Credit: Jared Beatrice.

One comment

  • This really is a great summary of a truly complex field. Without archaeology, we’d know very little about our past, especially about things that often go unrecorded, like living arrangements, the everyday devices and technology people used and the condition of the disenfranchised or lower classes of a society. Looking forward to more on the subject!