An evaluation of petrological techniques used in the study of medieval archaeology reviews some of the achievements; the first petrological analyses of medieval pottery were performed in Bonn in the 1930s. The two basic techniques of ceramic petrology are thin-section analysis and heavy metal analysis. Information can be determined regarding ceramic technology, e.g., glazing methods, firing techniques, brick manufacture when seen as metamorphosed sedimentary rock, and thus it is possible to assign pots to their geological source.