Laudine and Guenivere are two prominent characters in the works of Chretien. The primary difference between the two women is that Laudine has sovereignty, while Guenivere's power is solely derived from her husband, King Arthur. When Laudine's knight dies, it's clear that Laudine will control the castle and lands around it no matter who her knight is. Guenivere, on the other hand, has no rights to anything Arthur owns. In terms of temper,legal authority in terms of dealing with matters of the state, legal authority in choice of partners, Laudine holds the power, Guenivere doesn't. Even in terms of supernatural qualities, Laudine's abilities affect the physical world, while Guenivere seems limited to seeing things from afar.
At the beginning of the both tales, Laudine and Guenivere's living circumstances differed greatly. Meleagant, at the beginning of the Knight of the Cart, has captured many of Arthur's subjects. He barges into the court of Arthur, who does nothing to him. Meleagant taunts Arthur over the number of Arthur's subjects that Meleagant has already taken, and he tells Arthur that he's powerless to stop him from taking more. He makes a proposal to Arthur, that Arthur can send whatever knight to battle him, providing the night comes with Queen Guenivere. Should the knight win, Meleagant will free all prisoners and stop taking new ones. Should the knight lose, Meleagant will take Guenivere off. Arthur agrees to this. Kay, who is most malicious of the knights, says he will resign unless Arthur allows him to fight for Guenivere. And despite knowing that Kay loses every fight, Arthur agrees. Guenivere isn't apparently able to refuse to this agreement. Meleagant wins and takes Guenivere off. Guenivere was a token possession to be taken off. Laudine, on the other hand, when Yvain and the knight fought to the death, was the mistress of the castle. Effectively, Yvain won her love and thus status that she granted upon him when he won the fight. She was never in danger of losing her power or being diminished by the outcome of the fight.
Guenivere's overall temperament is very different from Laudine. Guinivere is the archetype of a “nice” woman in someways. She was kidnapped and held against her will, yet, when the King asks her to stop Lancelot from killing Meleagant, she complies. The King says he treated her will in captivity. However well she was treated, she was still held there against her will, away from her husband, Arthur. She, as a “good” obedient woman, she cannot truly seeks revenge. Laudine, on the other hand, could be quite merciless. When Yvain fails to return to her within the alloted time, she ends the marriage. Her maid is instructed to go to Yvain, make him return the magical ring, and convey to him that Laudine hates him, and that the marriage is over. After this Yvain becomes insane.
When she's kidnaped, Guenivere loses all of her servants and resources, while Laudine has everything she always had after the death of her knight. After she's taken away, Guenivere's a prisoner, and the only reason she isn't raped is that Meleagant's father is a decent man who has her protected. She's utterly at his mercy. Laudine, when her knight is killed, is surrounded by all of her servants and possessions. She's advised by an intelligent maid who uses magic (Laudine does herself, as well). When her maid suggests that she marry Yvain, she rather quickly agrees with the girl's logic. Guenivere seems to have no significant contact with other women, and in a way it shows how marginalized she is. She may have her maids as well, but she is never shown as having an intelligent conversation with another woman the way Laudine does with her maid.
While both Laudine and Guenivere had knights who would fight for them, Laudine's knights were her actual employees, while Guenivere merely had an affair with a knight. Lancelot would do anything and everything for Guenivere because he loved her. When she gave him her approval, no one could stand in his way during a fight. When she gave her disapproval, he lost fights. However, this is all because Lancelot was madly in love with her. Guenivere didn't give Lancelot his position in Arthur's court. Arthur himself did. The first knight and Yvain both worked for Laudine. While they both may have loved her, their position in her domain was granted to them by her. Laudine uses her knights to guard the fountain, because if it's disturbed, it can unleash massive thunderstorms against the castle, which would threaten the safety of her domain.
Guenivere isn't shown in Chrietien has having the power to have people executed in a legal sense, while Laudine has this power. She's not a reigning queen, but merely a queen consort. As such, no one follows her orders. If she wants someone taken down, she has two options. She has to convince Arthur to order the execution, but if he isn't willing, her will can be denied. Alternatively, she could whisper words in the ear of her lovesick lover, Lancelot. Though he's unlikely to refuse her, if he does, again, her will is blocked. When Laudine feels that her maid has betrayed her, she has the girl locked up in jail, waiting to be executed. And the girl wasn't the only one punished by Laudine, there were other prisoners as well. Laudine herself made the decision, and she doesn't need to get authority from a man in order to get her orders carried out. She's the sovereign herself.
Guenivere is the archetype of the damsel in distress, while Laudine can inflict violence. She never does anything to try to escape. Not only does she not fight, she doesn't try to trick the ones holding her captive, use her feminine wiles on them, or do anything that could get her out of her situation. All she does is wait for Lancelot to rescue her. She suffers from the unwanted attentions of Meleagant. Laudine, on the other hand, isn't defenseless. She tells Yvain she could kill him herself for killing her previous knight. Yvain, madly in love with her, begs for her forgiveness and for her love. She decides to grant him her love. Laudine, on the other hand, doesn't have unwanted suitors.
Also, as Laudine has the power to terminate her relationship anytime she wants to, Guenivere has no such power. She has an affair with Lancelot, but she can never openly love him. If her affair with Lancelot became known, Arthur could have both Lancelot and Guenivere executed for adultery, and Guenivere cannot divorce Arthur without his consent. She would lose her status as queen, and would become homeless. Laudine, when she ends the marriage with Yvain, isn't even worried about his services as a knight; she's the sovereign, and she manages just fine without him.
Both Laudine and Guenivere do have supernatural abilities. Laudine, of the two, has the greater abilities. Guenivere has a sort of divine knowledge. Without being anywhere near the scene when Lancelot jumps into the cart, Guenivere knows that he hestitated for a moment to jump on the cart. Laudine's supernatural abilities and knowledge go far beyond this. Laudine has a potion which she has her maid use to cure Yvain of madness. Her ring, which she had given to Yvain earlier, offered him protection. When she made him return it to her, that effectively cursed him and made him go mad. And of course, there's fountain she entrusts a knight to guard. And at least one of the women who works for Laudine, the maid, also has mystic abilities. It was the maid who first saved Yvain, had it not been for her, Yvain would have perished. The fact Laudine has another woman with mystic abilities working for her again shows her as the superior to Guenivere.
Overall, of the two women, Laudine, as the sovereign, is by far the most aggressive one, in terms of getting what she wants and in terms of getting what she wants. Guenivere, as merely the consort of the king, has to be sneaky in her affairs. Lancelot seems to be her true love, yet she doesn't have the power to chose to be with her true love. As the tales end, Laudine, the more powerful one, has the better ending. She gets to be together with Yvain, who she loves, for the rest of his life. While Guenivere is eventually rescued, she must return to her husband, and keep her affair with Lancelot well hidden.