Officially, human sacrifice was obnoxious "to the laws of gods and men." The practice was a mark of the "Other", attributed to Rome's traditional enemies such as the Carthaginians and Gauls. Rome banned it on several occasions under extreme penalty. A law passed in 81 BC characterised human sacrifice as murder committed for magical purposes. Pliny saw the ending of human sacrifice conducted by the druids as a positive consequence of the conquest of Gaul and Britain. Despite an empire-wide ban under Hadrian, human sacrifice may have continued covertly in North Africa and elsewhere.
What act did Romans view as obnoxious? To whom was human sacrifice usually attributed? What did Rome do about human sacrifice? As what  did the law of 81 BC view human sacrifice? What ruler banned human sacrifice empire wide?