This is the emblem of the Fabretti family, whose motto, "philois charisasthai echthron amynasthai", means roughly be nice to your friends, guard yourself against your enemies!
Title page of Inscriptionvm antiquarvm quae in aedibvs paternis asservantvr explicatio et additamentvm (1699), by Raffaele Fabretti.
Thank you to our Twitter friends for the mediaeval hedgehog facts!
. @joliheroics Carrying grapes on quills was mediaeval belief about hedgehogs. Ironically, not recommended for pet hedgehogs today. 2/2— Michael Hendry (@Curculiunculus) May 13, 2016
,@joliheroics hedgehog - no porcupines in Europe and spines all wrong. Ancients believed they stole apples and grapes by rolling on them.— Benenden Classics (@BenSchClassics) May 13, 2016