How can we tell what time period an artefact is from?

Archaeologists use the artefacts they dig up from the ground to learn more about the lives of people in the past. But did you know that there’s a technique called stratigraphy that archaeologists use to tell what period of history the artefacts came from? We used the artefacts from the Roman Baths Museum's collections to demonstrate how stratigraphy works. 

Stratigraphy handling table at the Roman Baths

Stratigraphy 

What is stratigraphy?

Stratigraphy refers to the study of stratas, or layers of the soil. Simply put, if an artefact is discovered in a layer further down in the soil, it is probably older than an artefact discovered higher up in the soil. If an artefact is found within the same layer as another artefact, it is generally considered to be from the same period.

Stratigraphy trays

 

Which of these objects were discovered deeper in the soil?

The artefacts in the tray on the left are from the prehistoric era, and would be found at a deeper level than the artefacts in the tray on the right, which are from the Victorian era. You can see an axe head, and an animal bone with marks of butchery in the prehistoric tray, but the artefacts in the Victorian tray, such as the key and decorated plate, are much more recognisable to the kind of objects we would use today!

Historical pottery 

Pottery from different time periods

The piece of Roman pottery is an example of mortarium, a type of kitchen ware used to grind up foods such as herbs, like a modern mortar and pestle. You can see the grit inside which helped the grinding process. Early Mediaeval pottery was often hand-made, with techniques such as stamping used for decoration, shown on our mediaeval pottery piece. As we can see by the Victorian pottery, Victorians used decorative tableware to show off their wealth. This era saw the introduction of transfer printed tableware, although this plate fragment is hand-painted. 

Think like an archaeologist? 

Can you guess where these pots were found in the soil?

It is very useful for archaeologists to analyse how the same type of artefact, such as pottery, appears in different soil layers, as then we can get a clearer idea of differences in methods, tools, and materials throughout history. Isn’t it interesting how artefact 2, the modern pottery, looks quite similar to artefact 3, the prehistoric pottery? Stratigraphy can show us how some objects can change so much throughout time, and how some objects seem to stay the same! 

 (Correct answers: A2, B1, C3) 

Ruby

Placement student