Seriation, also called artifact sequencing, is an early scientific method of relative dating, invented (most likely) by the Egyptologist Sir William Flinders Petrie in the late 19th century. Petrie's problem was that he had discovered several predynastic cemeteries along the Nile River in Egypt that seemed to be from the same period, but he needed a way to put them in chronological order. Absolute dating techniques were not available to him (radiocarbon dating wasn't invented until the 1940s); and since they were separately excavated graves, stratigraphy was no use either.
Petrie knew that styles of pottery seemed to come and go over time--in his case he noted that some ceramic urns from the graves had handles and others had just stylized ridges in the same location on similarly shaped urns. He assumed that the change in styles was an evolutionary one, and, if you could quantify that change, he surmised it might be used to indicate which cemeteries were older than others.
Petrie's notions about Egyptology, and archaeology in general, were revolutionary. His worrying about where a pot came from and what period it dated to and what that meant to the other objects buried with it were light-years away from the ideas represented in this photo dated to 1800, in which "Egyptian pots" was considered enough information for the thinking man. Petrie was a scientific archaeologist, probably close to our first example.
Sources and Further Information
- Timing is Everything: A Short Course in Archaeological Dating Techniques
- Sampling in Archaeology
See the bibliography for a list of sources and further reading.