The native Irish law or “Brehon law”, which was applied up to the mid-17th century, actually commanded that murderers be handed to the victim’s family. If the murderers failed to pay a fine, the family of the victim had a legal right to use them as slaves or kill them.
However, this was a last resort applied only if the convicted murderer failed to pay the two fines : a fixed one, known as a “body fine” or “man price” and an honor fine for the closest of kin to the deceased.
Only if the murderer couldn’t pay those two fines would the family of the victim be given three choices: wait for a delayed payment of the fines, take the murderer and sell him as a slave or kill him. This is considered by some the first step to the eradication of the capital punishment by encouraging monetary bails instead. Also, as Christianity preaches for forgiveness, the two fines could be considered both punishment and forgiveness for the murderer.
The first steps towards limitation or abolishment of capital punishment seem to have been made as early as medieval times.