La damnatio ad metalla degli antichi cristiani: miniere o cave di pietra?

The damnatio ad metalla issue is deeply linked to the spread of Christianity: in Sardinia evidence is patchy about time frame and location where martyrs Callisto (surely condemned eis métallon), Ponziano and Ippolito (both seemingly sent to exile) were kept. Recent research has shown that the condemned have served either in the mining areas of Sulcis or in the Gallura coast where granite was quarried. The analysis of the penal institution and the evolution of the meaning of the term metallum confirm that the expression ad metalla has the dual meaning of hard labour in mines and in quarries