Persecutions in lager scale by the authorities of the Roman Empire , began with the year 64 , when the Emperor Nero blamed them for the great Fire of Rome as the Roman historian Tacitus reported . Larger-scale persecutions followed at the hands of the authorities of the Roman Empire , beginning with the year 64 , when , as reported by the Roman historian Tacitus , the Emperor Nero blamed them for that year 's great Fire of Rome .