The book which later became known as Leicester's Commonwealth was written by Catholic exiles in Paris and printed anonymously in 1584.
It was published shortly after the death of Leicester's son, which is alluded to in a stop-press marginal note: "The children of adulterers shall be consumed, and the seed of a wicked bed shall be rooted out."
Smuggled into England, the libel became a best-seller with underground booksellers and the next year was translated into French.
Its underlying political agenda is the succession of Mary, Queen of Scots, to the English throne, but its most outstanding feature is an allround attack on the Earl of Leicester.
He is presented as an atheistic, hypocritical coward, a "perpetuall Dictator", terrorising the Queen and ruining the whole country.
He is engaged in a long-term conspiracy to snatch the Crown from Elizabeth in order to settle it first on his brother-in-law, the Earl of Huntingdon, and ultimately on himself.
Spicy details of his monstrous private life are revealed, and he appears as an expert poisoner of many high-profile personalities.
This influential classic is the origin of many aspects of Leicester's historical reputation.

In the early 17th century, William Camden saw "some secret constellation" of the stars at work between Elizabeth and her favourite; he firmly established the legend of the perfect courtier with the sinister influence.
Some of the most often-quoted characterisations of Leicester, such as that he "was wont to put up all his passions in his pocket", his nickname of "the Gypsy", and Elizabeth's "I will have here but one mistress and no master"-reprimand to him, were contributed by Sir Henry Wotton and Sir Robert Naunton almost half a century after the Earl's death.
The Victorian historian James Anthony Froude saw Robert Dudley as Elizabeth's soft plaything, combining "in himself the worst qualities of both sexes.
Without courage, without talent, without virtue".
The habit of comparing him unfavourably to William Cecil was continued by Conyers Read in 1925: "Leicester was a selfish, unscrupulous courtier and Burghley a wise and patriotic statesman".
Geoffrey Elton, in his widely read England under the Tudors (1955), saw Dudley as "a handsome, vigorous man with very little sense."

Since the 1950s, academic assessment of the Earl of Leicester has undergone considerable changes.
Leicester's importance in literary patronage was established by Eleanor Rosenberg in 1955.
Elizabethan Puritanism has been thoroughly reassessed since the 1960s, and Patrick Collinson has outlined the Earl's place in it.
Dudley's religion could thus be better understood, rather than simply to brand him as a hypocrite.
His importance as a privy councillor and statesman has often been overlooked, one reason being that many of his letters are scattered among private collections and not easily accessible in print, as are those of his colleagues Walsingham and Cecil.
Alan Haynes describes him as "one of the most strangely underrated of Elizabeth's circle of close advisers", while Simon Adams, who since the early 1970s has researched many aspects of Leicester's life and career, concludes: "Leicester was as central a figure to the 'first reign' [of Elizabeth] as Burghley."
The book which later became known as Leicester's Commonwealth was written by Catholic exiles in Paris and printed anonymously in 1584. It was published shortly after the death of Leicester's son, which is alluded to in a stop-press marginal note: "The children of adulterers shall be consumed, and the seed of a wicked bed shall be rooted out." Smuggled into England, the libel became a best-seller with underground booksellers and the next year was translated into French. Its underlying political agenda is the succession of Mary, Queen of Scots, to the English throne, but its most outstanding feature is an allround attack on the Earl of Leicester. He is presented as an atheistic, hypocritical coward, a "perpetuall Dictator", terrorising the Queen and ruining the whole country. He is engaged in a long-term conspiracy to snatch the Crown from Elizabeth in order to settle it first on his brother-in-law, the Earl of Huntingdon, and ultimately on himself. Spicy details of his monstrous private life are revealed, and he appears as an expert poisoner of many high-profile personalities. This influential classic is the origin of many aspects of Leicester's historical reputation.
In the early 17th century, William Camden saw "some secret constellation" of the stars at work between Elizabeth and her favourite; he firmly established the legend of the perfect courtier with the sinister influence. Some of the most often-quoted characterisations of Leicester, such as that he "was wont to put up all his passions in his pocket", his nickname of "the Gypsy", and Elizabeth's "I will have here but one mistress and no master"-reprimand to him, were contributed by Sir Henry Wotton and Sir Robert Naunton almost half a century after the Earl's death. The Victorian historian James Anthony Froude saw Robert Dudley as Elizabeth's soft plaything, combining "in himself the worst qualities of both sexes. Without courage, without talent, without virtue". The habit of comparing him unfavourably to William Cecil was continued by Conyers Read in 1925: "Leicester was a selfish, unscrupulous courtier and Burghley a wise and patriotic statesman". Geoffrey Elton, in his widely read England under the Tudors (1955), saw Dudley as "a handsome, vigorous man with very little sense."
Since the 1950s, academic assessment of the Earl of Leicester has undergone considerable changes. Leicester's importance in literary patronage was established by Eleanor Rosenberg in 1955. Elizabethan Puritanism has been thoroughly reassessed since the 1960s, and Patrick Collinson has outlined the Earl's place in it. Dudley's religion could thus be better understood, rather than simply to brand him as a hypocrite. His importance as a privy councillor and statesman has often been overlooked, one reason being that many of his letters are scattered among private collections and not easily accessible in print, as are those of his colleagues Walsingham and Cecil. Alan Haynes describes him as "one of the most strangely underrated of Elizabeth's circle of close advisers", while Simon Adams, who since the early 1970s has researched many aspects of Leicester's life and career, concludes: "Leicester was as central a figure to the 'first reign' [of Elizabeth] as Burghley."
Robert Dudley, 1st Earl of Leicester