|Affiliated with:||Milady de Winter|
|Family:||Adele Bessette (Mistress)|
|First seen in:||Friends and Enemies|
|Final appearance:||Musketeers Don't Die Easily|
|Main actor:||Peter Capaldi|
Cardinal Richelieu was a real person in history (Armand Jean du Plessis, Cardinal-Duke of Richelieu and of Fronsac). In real life, Richelieu lived from 1585 to 1642, and was succeeded in his position as cardinal and First Minister of France by Cardinal Mazarin.
The Cardinal returned from state affairs to his residence in Paris to find his mistress, Adele Bessette. He was suspicious as one window was open, owing for the cold temperature. Later, while the King was shooting birds for sport, Armand informed him of troubling reports concerning rampaging Musketeers. He persuaded the King to start an inquiry into the reports, much to Treville's dismay.
At Athos' trial, the Cardinal accused him of highway robbery and murder. He brought forward witnesses, an Innkeeper and a Coachman who indirectly accused the Musketeer of the crime. The Cardinal vowed that it was the King's decision what should happen to the accused. He was pleased when the King decided to execute Athos as an example. In a secret meeting, the Cardinal met with Milady de Winter to thank her for choosing Athos as the target for their plans, but he warned her that killing Raul Mendoza was a mistake. Despite this, he took the letters from Milady and claimed that without these, the King would put more faith in him rather than the Musketeers. Cunningly, Richelieu confronted the King later to discuss France's inevitable war with Spain and persuaded the King to reveal the plot about the letters.
Believing her to be a traitor and a spy, the Cardinal escorted his wife, Adele, to the outskirts of Paris to be murdered. In her dying words, he heard her honour the Musketeer, Aramis. Deviously, he sent the musket back to Aramis to scare him. At the Chatelet, the Cardinal met with Dujon and thanked him for not accusing him of planning the entire frame on Athos. However, he offered Dujon a poisoned drink to stop him from speaking again.
In the crisis where criminal Vadim had escaped the Chatelet, the Cardinal entrusted Treville and his Musketeers to find him immediately. He also entrusted the job to Milady de Winter, recalling how trustworthy she had been over five years of service. After hearing news about D'Artagnan from Treville and Athos, the Cardinal deduced that Vadim was planning to kill the King and Queen after Easter mass outside the Notre Dame. When informing the King of the plot, the Cardinal could not persuade the King and Queen to cease the tradition for the sake of a potential assassination.
At the Easter mass, the Cardinal was escorted just like his King and Queen to a carriage out of sight of the attackers. After Vadim had been reprimanded and killed, the Cardinal questioned Milady about the whereabouts of the stolen diamond pendant. He was disappointed to find that it was still lost.
Informing Milady of the Musketeer mission to locate Emile Bonnaire, the Cardinal was worried to hear that she wanted some time off to deal with her personal life. He believed that she might interfere with the mission. Later, he visited the King to inform him of the matter, and how Bonnaire's actions were breaking the treaty between France and Spain.
The Cardinal had a personal meeting with Bonnaire when he arrived in Paris. He informed the merchant trader about breaching the laws of the land, and what consequences it might have. However, he did allow Bonnaire to lay out his plans.
At the parade for the arrival of the Duke of Savoy, the Cardinal reminded the King that the Duke was a very important individual in the influence between Spain and France. When the Duke finally arrived, Richelieu was indifferent at being insulted. He was infuriated to hear, after an assassin had tried to kill the duke, that he would not be signing the treaty until the culprit was caught. Treville later accused him of employing the assassin, but the Cardinal was able to dissuade his accusations. They both agreed that the Duke needed to be kept away from Cluzet whatever the cost.
As a way of taunting Cluzet, the Cardinal visited him in the Chatelet, revealing that the Duke had arrived to sign a treaty that would bring France and Spain together. Aware of the Chancellor's denial, the Cardinal informed him that he would never advise the Duke again. Attempting to speed up the deliberations for the signing of the treaty, the Cardinal met with the Duke in the palace and was baffled to hear that the Duke wished to duel a Musketeer to decide whether the treaty should go ahead or not. Watching the fight, the Cardinal was pleased that Athos won.
When he heard from Treville that the Musketeers had started asking questions about the past, the Cardinal told him to handle it in his own way, as a matter of political strength was at stake. In the presence of the King, the Cardinal met with the Duke to make a final stab at completing the peace negotiations, but was accused of lying instead. The Duke claimed that he had irrefutable proof that Cluzet had been captured by Paris soldiers and brought to Paris. The Cardinal was forced to follow him to meet the ex-Chancellor.
At the Chatelet, he was forced to allow the Duke entry to the prison. When he reached the cell, however, he realised that the Musketeers had already taken care of the matter by swapping a decoy for Cluzet in his cell. Confident and pleased, he gave the Duke another chance to sign the treaty. On his way out, he thanked the Musketeer, D'Artagnan who was acting as the jailer. Back at the palace, the Cardinal lead the arrangements for the treaty that bound France and Savoy together.
When King Louis was planning to reconstruct parts of Paris, the Cardinal was wary of forcing the people out of the Court of Miracles, believing them to be criminals. Emile de Mauvoisin later visited the Cardinal with plans to destroy the Court of Miracles, which he would later sell to the King. Richelieu was surprised to learn that the plan was already being executed that day. This plan was foiled, however, by the Musketeers, and Emile later committed suicide.
The Cardinal arranged with the Musketeers to have Agnes and her child taken to Paris. Concurrently, the Cardinal attended the King's hunting party, which was interrupted by the unexpected arrival of Louis' mother, Marie de Medici. In spite of what was said in the past, the Cardinal advised the King not to have her executed.
Sometime before the events of Series 2, the Cardinal passes away and his funeral is attended by the King and the Musketeers. His position as First Minister was initially offered to Treville, who declined the offer. The position was later given to Comte de Rochefort, who was one of the Cardinal's agents.
The Cardinal is considered to be a very devious man, who uses his position to manipulate the administration of France. Leader of the Red Guards, and a man who dislikes the Musketeers, he uses his leadership to try and frame the Musketeers in order for the King to lose faith in them and their captain, Treville. When he heard that D'Artagnan had escaped with Vadim in the terror plot crisis, the Cardinal was indifferent as to the trainee Musketeer's fate. Believing himself to be superior, the Cardinal taunts the ex-chancellor of Savoy, Cluzet, about the arrival of the Duke in Paris in his cell in the Chatelet.
Ultimately, he is an intelligent individual who is able to conform spies and agents to do his bidding and provides enough scare factor with his position to keep them obedient. As with the case of Dujon, the soldier remained loyal, despite the Cardinal's uncertainty about him. He singlehandedly manipulates the Savoy government in order to capture the ex-chancellor and ensure France has more influence than Spain.
Mainly, the Cardinal is cruel and callous and would kill anyone who disobeyed him or got in his way. When he discovered that his mistress was sleeping with the Musketeer Aramis in his own bed, the Cardinal brought her out into the woods and had her executed by his guards who shot her in the back of the head. 
Richelieu is able to use the King's ignorance to his advantage and projects a wise fatherly figure in order for the King to put his faith in him. The Cardinal likes to continually remind the King of the impending war between France and Spain. Both he and the King worked together in protecting the identity of their agent, the Duchess of Savoy by capturing the ex-chancellor of the principality.
Milady de Winter
Milady has been in the Cardinal's service for five years, but he still does not trust her entirely.
The Cardinal respects Milady like no other spy. He finds her attractive and cunning, similar to himself and is predominantly satisfied as she completes the task that he gave her. However, there is a sense of worry for him that she would allow her own personal feelings to come first someday.
There's somewhat of a love-hate relationship between the two characters. They have a dynamic that is very entertaining to watch. He does not like the King's overwhelming faith in the Musketeers, and Richelieu continues to plot to try and break that faith. The Cardinal once used Treville in order to distract the Duke of Savoy while he captured the ex-chancellor. This inevitably lead to the death of a number of Musketeers. However, the Captain and the Cardinal have respect for each other and have been begrudging allies on multiple occasions.