[no object]Especially of a dead body, soul, etc.: to rest, repose.
In later use in conscious translation of the Latin phrase requiescat (also requiescant) in pace..
Origin
Mid 17th century; earliest use found in Thomas Urquhart (1611–1660), author and translator. From classical Latin requiēscere to take repose, rest from re- + quiēscere to come rest, to be quiet.