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."
When the Medici family returned to power in Florence in 1512, Machiavelli was removed from his post in the city's chancery because of his association with the head of a rival faction.
His name was then linked with a conspiracy to overthrow the Medici. They issued the proclamation found by Prof Milner for his arrest.
"On the same day, he was imprisoned, tortured and later released and placed under house arrest outside the city," said the historian, an authority on Renaissance Italy.
Machiavelli, known as the Prince of Darkness, then wrote The Prince in the hope of regaining the approval of the Medicis.
"But there's no evidence to suggest they even read it," said Prof Milner, who is Visiting Professor at the Harvard Centre for Italian Renaissance Studies at Villa I Tatti in Florence.
Machiavelli's fortunes spiralled downwards and he died in abject poverty 14 years later.
The academic found the document while studying hundreds of town crier proclamations issued between 1470 and 1530.
He also found documents relating to the payment of four horsemen who scoured the streets of the Tuscan city for Machiavelli.
Florence is this year celebrating the 500th anniversary of Machiavelli's writing of The Prince, a political treatise which argues that the pursuit of power can justify the use of immoral means.
The celebrations include, on February 19, a reconstruction of the events surrounding his arrest and imprisonment.
His name was then linked with a conspiracy to overthrow the Medici. They issued the proclamation found by Prof Milner for his arrest.
"On the same day, he was imprisoned, tortured and later released and placed under house arrest outside the city," said the historian, an authority on Renaissance Italy.
Machiavelli, known as the Prince of Darkness, then wrote The Prince in the hope of regaining the approval of the Medicis.
"But there's no evidence to suggest they even read it," said Prof Milner, who is Visiting Professor at the Harvard Centre for Italian Renaissance Studies at Villa I Tatti in Florence.
Machiavelli's fortunes spiralled downwards and he died in abject poverty 14 years later.
The academic found the document while studying hundreds of town crier proclamations issued between 1470 and 1530.
He also found documents relating to the payment of four horsemen who scoured the streets of the Tuscan city for Machiavelli.
Florence is this year celebrating the 500th anniversary of Machiavelli's writing of The Prince, a political treatise which argues that the pursuit of power can justify the use of immoral means.
The celebrations include, on February 19, a reconstruction of the events surrounding his arrest and imprisonment.