AD METALLA. — Condemnation to hard labour in the mines *a. m.* was, after the death penalty, the most severe punishment, hence called *proxima morti* (Dig. XLVIII, 19, 28). Unknown in the Republic, it was introduced by Tiberius in 23 AD to punish plebeians and slaves guilty of crimes against the State or of communal offences, without regard to age or sex; later it was frequently applied against Christians.
It was generally a perpetual penalty, but if the sentence did not specify this, it was considered a ten-year term (Dig. XLVIII, 19, 22). A free man lost his liberty and became the property of the State, a slave of his punishment, *servus poenae* (Dig. XXVIII, 1, 8, 4). The penalty was preceded by flogging; the condemned were branded, their heads shaved on one side (semitonsi, Cyprian *Ep. 76*, 2), chained (compedes), their feet held by cross-bars (*traversaria*), forced to sleep on bare ground, with insufficient food and clothing. Between the penalty *a. m.* and that *in opus metallum* there was no other difference than in the chains, which were lighter in the second case. Women were generally assigned to auxiliary work in the service of the mines: *in ministerio metallicorum* or in the salt-works; they retained their citizenship if condemned for a fixed term.
Dionysius, Bishop of Corinth, wrote in 170 to Pope Soter (166–75) thanking him because the Community of Rome «supports the brethren who groan in the mines; by this liberality which you have practised from the earliest times you have remained faithful to a tradition inherited from your Roman fathers, which your worthy Bishop Soter has not only confirmed but increased and strengthened» (Eusebius, *Hist. Ecc.*, IV, 23, 10). Tertullian also attests that aid was given to Christians condemned to the mines: *si quis in metallis, dumtaxat ex causa Dei sectae* (Apol., 30). Under the Emperor Commodus (176–92) a group of Christians worked in the mines of Sardinia, for whom Marcia obtained a pardon from the emperor; among them was Callistus (Hippolytus, *Philosophumena*, IX, 2; PG 16, 3). To a band of African bishops, deacons and laymen condemned to the mines in 257 «in metallis constitutis... martyribus Dei Patris» the Bishop of Carthage St Cyprian sent substantial aid collected from the faithful of his community (Cyprian, *Ep. 77*: *PL* 4, 427 ff.). The condemned replied with three letters preserved in the collection of St Cyprian’s epistles (*Ep. 78–80: ibid.*, 434–36). The mines could be of marble or of metals, etc., in Sardinia, Greece, Africa, Egypt, Palestine, where, especially in the copper quarries of Piaenos, the extraction work was particularly arduous (Eusebius, *De Martyrib. Palestinae*, VII–VIII: PG 20, 1481 ff.). In the Ambrosian liturgy there was preserved an *oratio pro fratribus in metallis constitutis*; in the *Missale Gothicum* there is a prayer *pro fratribus et sororibus in metallis deputatis*.