On the Eve of Urbanization: Bayesian Model Dating for Medieval Turku

The era of early urbanization in Finland coincides with large variations in the atmospheric radiocarbon concentration around the 13th-14th centuries AD. Therefore, the uncertainties of an individual C-14 date are too large to support studies of this time period effectively. In this work, we have employ tree-ring wiggle-matching methodology and used Bayesian modeling of dates to account for stratigraphical a priori information within Aboa Vetus Museum, Turku, Finland. The wiggle-match method helps significantly to overcome the calibration-curve-induced challenges within C-14 dating. The results of the dating model agree with the typological dates of the archaeological finds and illustrate a gradual evolution of urbanization in one of the oldest cities in Finland.