In order to establish the antiquity of the many cultures which developed in the past, archaeologists study the superposition of layers that form over time and the material found within such layers.
The study of the contents of tombs, particularly pottery artifacts, enables experts to identify the culture to which the interred individuals belonged. Some of the pottery fragments excavated from stratigraphic layers are particularly “diagnostic”; in other words, their shape and designs and the techniques employed enable the identification of the culture to which they belonged and the establishment of their chronology.
Rafael Larco Hoyle applied his extensive knowledge of agronomy and climatic conditions to the study of the stratigraphic layers uncovered during his excavations. The dates established by his chronological ordering were remarkably accurate and to this day are still used by modern archaeologists.