 Christian captives enslaved were a particular concern, and their trafficking to non-Christian owners regarded as especially disgraceful; this was repeatedly forbidden by the church and many figures from the Early Medieval to Early Modern periods took part in the buying back of Christian slaves from their non-Christian owners.One of the traditional Seven Acts of Mercy is now usually given as the "ransoming of captives", but this originally meant slaves or prisoners of war, a distinction that mostly emerged during the Middle Ages, as the sale by Christians of their prisoners became unacceptable, though holding those likely to produce a ransom as prisoners for long periods was not.The liberation of their own slaves or the buying of slaves to liberate them is a constant theme in early medieval hagiographies.