167 CHAPTER 9 Naturam ars imitata: European Brassmaking between Craft and Science THILO REHREN AND MARCOS MARTINÓN-TORRES ABSTRACT This chapter presents a summary of analytical work on medieval brassmaking crucibles, spanning more than half a millennium and tracing what is believed to be a gradual development of increasing skill and efficiency of the craftspeople who used these crucibles. This summary is then contrasted to a similarly diachronic sequence of textual sources concerned with brassmaking, illuminating the discrepancy between the matter-of-fact practitioners’ reports and the somewhat befuddled attempts of philosophers of nature to understand and explain the essence of brass as opposed to copper. The different strands of knowledge generation and transfer, namely, observation and apprenticeship versus theoretical consideration and text, are placed into the changing scholarly environment from the High Middle Ages to the Renaissance. This exercise provides fresh insight not only into the development of brassmaking technology but also into the driving, or otherwise, forces in technological developments in general. The comparison of archaeological, scientific, and historical evidence is used to demonstrate the potential of such multisource studies. Introduction Brass has a more chequered history than most other alloys do, so much so that despite more than three millennia of brass use, it finally was acknowledged as an alloy only less than 500 years ago. For most of its history, brass caused wonder and stimulated the minds of people trying to understand what it really was – a process that in some sense continues to