This paper consists of a discussion of how modern chemical methods can be used to examine both ancient and medieval artifacts. Archaeological work in Israel involved analysis of ancient pigments and dyes found on excavated materials from caves in the Judean desert and the ancient fortress of Masada. Pigments in medieval manuscripts formed the basis of further work on colorants. In addition, medieval artists' manuals were examined for recipes for blue pigments which were then carried out and characterized with some surprising results.