The fortress of the Teutonic Order in South-eastern Europe: Feldioara/Marienburg from early foundation to present-day; preliminary archaeometric studies

Abstract Feldioara has long been regarded as the headquarters of the Teutonic Knights during their brief Transylvanian period (1211–1225), but neither history nor archaeology could provide compelling evidence based solely on traditional methods. By radiocarbon dating mortars (sub-micron calcite fraction separation followed by chemical digestion with polyphosphoric acid before AMS target formation), it was finally determined that the earliest defensive constructions of the fortress did indeed date from the Teutonic period. The absolute chronology data were integrated in the preexisting relative chronology, stratigraphy, and documentary data. The composition of genuine calcite fractions was analyzed using FT-Raman spectrometry before AMS measurements. By exploring the OxCal Program features we were able to establish an absolute chronology spanning from the 12th century to the beginning of the 19th century.