Prof Stephen Milner from Manchester University discovered the historic document by accident while researching town criers and the proclamations they read out in archives in Florence.
The 1513 proclamation, which called for the arrest of Machiavelli, eventually led to his downfall and death.
"When I saw it I knew exactly what it was and it was pretty exciting," said Prof Milner.
"When you realise this document marked the fall from grace of one the world’s most influential political writers, it’s quite a feeling.
“The Prince is a seminal work, with a lasting influence on political thought and culture. The term ‘Machiavellian’ and the naming of the Devil as ‘Old Nick’ all derive from this single work, but the circumstances of its composition have often been overlooked.” Read more.