An amercement is a financial penalty in English law, common during the Middle Ages, imposed either by the court or by peers. Amercments are much mentioned in Magna Carta, particularly article 20:"A free man shall not be amerced for a trivial offence except in accordance with the degree of the offence, and for a grave offence he shall be amerced in accordance with its gravity, yet saving his way of living; and a merchant in the same way, saving his stock-in-trade; and a villein shall be amerced in the same way, saving his means of livelihood--if they have fallen into our mercy: and none of the aforesaid amercements shall be imposed except by the oath of good men of the neighbourhood. " While it is often synonymous with a fine, it differs in that a fine is a fixed sum prescribed by statute and was often voluntary, while an amercement is arbitrary.
