Ascendancy of the Catholic League
On 7 July 1585 Henry III was forced to sign the Treaty of Nemours with Catherine's brother Henry I of Guise and the Catholic League.
On 18 July 1585 he signed an edict that cancelled all previous edicts of tolerance, paid mercenaries of the Catholic League from the royal treasury and prohibited Protestantism.
The Guise party received favors and positions, while Henry of Navarre, the future Henry IV of France was disinherited.
However, the king did not give the Guises enough support to defeat the Protestants, and the conflict dragged out.
Henry III proposed to marry Catherine to his favorite Jean Louis de Nogaret de La Valette, but Catherine flatly refused to marry him.
Jacques Auguste de Thou and Pierre de L'Estoile, both hostile to Catherine, portrayed her as directing League propaganda, and called her "the governess of the League in Paris."
In July 1587 a board was erected in the cloister of Saint Sévérin that represented the sufferings of Catholics under Queen Elizabeth I of England.
The final scene was the execution of Mary, Queen of Scots.
It was generally thought that Catherine de Montpensier was responsible for the board, which was viewed by many people each day.
The board probably used images from the Theatrum Crudelitatum haereticorum nostri temporis of Richard Rowlands, who had been paid large sums of money by King Philip II of Spain for activities that would undermine support for Henry III.
Catherine's enemies were not inactive.
The Library of the Duchess of Montpensier, published in 1587, tried to discredit her and other women of the court with a satirical list of imagined titles that implied sexual voracity and infidelity.
One was entitled "Inventory of the Proportions of French Cocks, with the Great Balls of Lorraine, by Madame de Nermoutier".
This referred to rumoured liaisons between Charlotte de Sauve, Marquise de Noirmoutier, with Henry of Guise, Henry of Navarre and the king's brother Francis, Duke of Anjou.
Catherine controlled the media and sent bulletins to the preachers telling them what news to preach.
According to Pierre de L'Estoile she bribed the preachers and curates to convey her message with money and offers of bishoprics, abbeys and other valuable offices.
She could do this since her brother Louis II Cardinal de Lorraine was the leading prelate in France.
In January 1588 Henry III asked her to leave Paris due to her hostile activity.
He said she had done more for the League than any army.
Fighting broke out in Paris on 12 May 1588 and about 60 of the king's soldiers were killed.
The next day the Bastille fell, Catherine's brother Henry I of Guise took control of Paris and Henry III of France fled to his Château de Blois.
The Parlement of Paris began a trial of Henry III.
Catherine now considered herself queen of Paris.
She took to wearing a pair of scissors at her belt that she said she would use to tonsure the king before locking him up in a monastery.
On 23 December 1588 Henry III of France arranged for Henry I of Guise to be assassinated at the Château de Blois.
The next day Catherine's younger brother Cardinal Louis II was also assassinated at the Château de Blois.
The bodies of both men were burned and their ashes thrown into the Seine.
The deaths of two of her brothers confirmed Catherine in her hatred of King Henry III of France.
Her third brother Charles, Duke of Mayenne, now became the leader of the league.
Catherine was a woman warrior in the French tradition.
In 1588 she led the resistance to Henry of Navarre wearing a soldier's helmet and brandishing a sword.
