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How does cross dating help archaeologists date an undated site?

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Archaeology Archaeologists mapping their finds at Pachacamac, Peru, an Indigenous town occupied from approximately 200 bce to 1532 ce, when it was sacked by conquistadors under the command of Francisco Pizarro.

Cross dating is a technique used by archaeologists to establish the chronology of an undated site by comparing its artifacts with those from another site or culture that has a known date.12

This method relies on the principle that if an object from a known culture—such as a specific style of pottery—is found at an undated site, the material discovered alongside it is likely contemporary with that imported object. Conversely, if an object from an undated culture is discovered at a site with a known date, the undated culture can be assigned a chronological timeframe based on that contact.2

This technique is particularly valuable for dating nonliterate communities through their interactions with literate ones. Historically, it was pioneered by Sir Flinders Petrie, who used it to date Palestinian and Aegean sites by referencing Egyptian chronologies. It remains a foundational method for establishing the prehistoric timelines of regions like Europe, where Neolithic, Bronze, and Iron Age chronologies were largely built by cross dating with the ancient Near East.2