The Cardinal was regarded with displeasure by Queen Marie Antoinette for having spread rumors about the Queen's behavior to her formidable mother, the Holy Roman empress Maria Theresa.
The Queen had also learned of a letter in which the Cardinal spoke of Maria Theresa in a manner that the Queen found offensive.
In the meantime, Louis XV died of smallpox, and his grandson and successor banished du Barry from the court.
It was described as “a row of seventeen glorious diamonds, as large almost as filberts…
On 21 January 1785, Jeanne told the Cardinal that Marie Antoinette wanted to buy the necklace; but, not wishing to purchase such an expensive item publicly during a time of need, the Queen wanted the Cardinal to act as a secret intermediary.
A little while later, Rohan negotiated the purchase of the necklace for 2,000,000 livres, to be paid in installments.
The Affair of the Diamond Necklace was an incident from 1784 through 1785 at the court of King Louis XVI of France involving his wife, Queen Marie Antoinette.
The reputation of the Queen, already tarnished by gossip, was ruined by the implication that she participated in a crime to defraud the crown jewelers in acquiring a very expensive diamond necklace.
The event is historically significant as one of the events that led to the French populace's disillusionment with the monarchy, which, among other causes, eventually precipitated the French Revolution.
In 1772, Louis XV of France decided to make Madame du Barry, with whom he was infatuated, a special gift at the estimated cost of 2,000,000 livres (approximately million in 2015 USD).