nature and distribution of artifact assemblages across space and time (as defined by the chronological relationships established through stratigraphy and typology). Such research allowed archaeologists to document a phenomenon in the human use of material culture that had temporal implications. Put simply, seriation acknowledges that artifacts change in their forms and in their styles of decoration over time. Archaeologists such as Petrie were able to use empirical evidence from excavations to establish that change in such forms and styles had a history that was generally repeated—an artifact in its earliest appearance was rare, it then became more popular (and hence more numerous), and, as fashion moved on, it eventually became rare once again before finally vanishing. Petrie’s great contribution to the method of seriation was to harness his empirical information to construct frequency diagrams for artifacts of various types at various stratigraphic levels, thus creating “battleship curves” that plotted the “life histories” of artifact form and style.

Notwithstanding the great advances made in relative chronologies based on the analysis of artifacts and their stratigraphic contexts, archaeologists were significantly hampered by their inability to quantify time. Without quantifiable time they could establish the direction of history, but they could not explore significant elements of process that require a means of establishing rate and duration. The establishment of high human antiquity, which was first achieved in the mid–nineteenth century by scholars such as hugh falconer, joseph prestwich, édouard lartet, and jacques boucher de perthes, was limited in its impact precisely because it was essentially based on relative chronology. Archaeologists had to wait until well into the twentieth century before reliable means of establishing the absolute ages of objects or their stratigraphic contexts could be established, but when this was achieved the practice of archaeology was transformed to its core.

Of course, archaeologists had long been aware that ancient societies had their own sense of time and succession, creating calendars that, when deciphered (as in the case of mesoamerican calendrical systems), provided absolute dates with great precision. Indeed, it was the linking of these calendars and lists of kings and dynasties (especially in Egypt and the Middle East) that allowed Petrie and Montelius (and, of course, vere gordon childe) to construct a notional “history” for late-European prehistory. However, although it was widely accepted that constructing such histories was a valuable undertaking, it was also understood that the reliability of such histories rested on assumptions about duration and processes that were difficult to independently test. Dates derived from the study of ancient coins and inscriptions certainly assisted (and continue to assist) the archaeologist in refining chronology, but of themselves they did not overcome the limitations of the approach. This accomplishment had to wait for the application of science-based dating methods to archaeology.

During the twentieth century archaeologists were presented with a constant flow of techniques for dating either archaeological objects or archaeological contexts or both. The first of these, dendrochronology, or tree-ring dating, was pioneered by a. e. douglass in the first two decades of the century. Although it was originally developed in the Southwest of the united states, the technique has been used in other parts of the world with varying degrees of success (Baillie 1982). The story of dendrochronology mirrors that of other science-based dating technologies in the twentieth and twenty-first centuries in that the techniques themselves become the subject of continuing research and development. Although the great proliferation in absolute dating technologies that occurred in the twentieth century has often been explained as stemming from a desire to encompass more time with greater precision, it is also true that the archaeological scientists who create and employ such techniques also need to devote considerable research time to understanding their nature, prospects, and limitations.

This is perhaps most apparent in the development and application of radiocarbon dating. Given that this was the first dating technology that depended on the establishment of regular, time-dependent processes (in this case radioactive decay), archaeologists and archaeological scientists have been researching C-14 dating