Darn, none of the 20thc historian are that much fun! Saint-Just 'Harolding'! (as in 'Harold and Maude'). Oh, this just gets better!
Actually - though I can't really see it happening (well, maybe!)- it wouldn't be too hard to get skulls in the days of shallow graves and catacombs and above-ground tombs...there was a man going round the Glastonbury Festival one year with a sack of them he'd obviously nicked from a crypt-clearance! He was selling them at £50 a head...