fired clay or terracotta was also widely employed in the roman period for architectural purposes, as structural bricks and tiles, and occasionally as architectural decoration, and for the manufacture of small statuettes and lamps. these are not normally classified under the heading 'pottery' by archaeologists, but the terracottas and lamps will be included in this article. pottery is a key material in the dating and interpretation of archaeological sites from the neolithic period onwards, and has been minutely studied by archaeologists for generations. in the roman period, ceramics were produced and used in enormous quantities, and the literature on the subject, in numerous languages, is very extensive.