It is not a work of art: it is a graffito, carved deep into the Istrian stone. A quite respectable rat, long curved tail, and above it a date in Roman numerals, 1644 according to those who have read it up close (some also read 1643: the column has been whitewashed and the last digit is hard to decipher). Someone, almost four centuries ago, saw a pantegana (rat) so memorable as to fix it in the wall for ever.