Also, the Romans, being Romans, one cannot but wonder if they didn't excavate Silbury itself. Then again (whatever their other vices) the Romans do seem to have respected native beliefs (as long as those beliefs didn't threaten the power of Rome). Must have been quite a dilemma for the Roman engineers and historians of the day - to tunnel Silbury or not to tunnel. If the Romans had such a town (wonder what they called it?) surrounding Silbury and didn't tunnel the monument that in itself indicates either A) their respect for native beliefs or B) the strength of local/indigenous feeling at the time :-)