Mobility and diet in Gallo-Roman Belgium: The case of Tienen (AD 1st-4th c.)

The Gallo-Roman vicus of Tienen (Belgium, 1st-4th c. AD) presents, to date, the biggest Gallo-Roman cemetery of the Low Countries. The >1400 cremation deposits excavated within the southwestern cemetery provided a unique opportunity to investigate patterns of mobility through strontium (Sr) isotope (87Sr/86Sr) and concentration analysis ([Sr]). Over 140 individuals, from varying chronologies, types of funerary deposits and locations, were sampled for analysis. Results provided insights on the mobility, as well as dietary practices, of the occupants of the vicus. Mobility seems to have been minimal in Tienen, but the archaeological material found within the vicus suggests that these mobility signals were potentially masked by salt intake. Indeed, this may have increasingly affected the Sr isotope ratios of the individuals throughout the four phases of occupation defined in the site, skewing them towards the marine Sr value (0.7092). This phenomenon is in agreement with what has been previously observed in Belgium for the Roman period, where a shift towards a higher salt production and consumption at the transition between the Metal Ages and the Roman period is detectable in the Sr values of humans. Overall, this research highlights the potential of Sr analysis in cremated remains, going beyond an assessment of mobility towards an investigation of dietary patterns, opening new lines
of understanding for Roman populations.