Over and over again, people admire D'Artagnan for his loyalty, bravery, cleverness, and skills at fencing and horseback riding. (Check out the Shmoop guide to The Three Musketeers if you want some good sword fights.) Out of the four original Musketeers, D'Artagnan is the only one who remained in the King's service, eventually becoming captain. In this position, he is the King's muscle man, doing all the arresting, fighting, and rescuing. His prolonged service to the King is evidence of loyalty to the crown of France. This loyalty is tested in The Man in the Iron Mask time and again as D'Artagnan is required to execute deeds with which he doesn't agree. Read on for more.
As early as Chapter Fourteen, D'Artagnan has already suspected Aramis of plotting against the King. And his response on the matter is immediate and decisive: "Aramis, I will do more than remain neutral – I will save you" (14.92). And when the time comes, thirty chapters later, D'Artagnan does everything in his power to do so. For D'Artagnan, his friends unquestionably come first. Even when he is promised a marshal's baton – the pinnacle of achievement – for capturing or killing Porthos and Aramis at Belle-Isle, D'Artagnan again does not hesitate: "Poor Porthos! poor Aramis! No; my fortune shall not cost your wings a feather" (61.112). Not many men in The Man in the Iron Mask are made of the same moral fiber.
D'Artagnan's unwavering commitment to his friends gets him in deep trouble with King Louis. Let's go over the sequence of events.
Event #1: D'Artagnan does not hesitate to arrest Philippe, (the false King), and dutifully escorts the man to the remote island of Ste. Marguerite. Even when Philippe saves his life, D'Artagnan still obeys orders and locks him up for life. D'Artagnan's not exactly happy about this, because he likes Philippe, but he complies with the King's orders.
Event #2: D'Artagnan really does not want to arrest Fouquet – in fact, he tries numerous times to drop hints to Fouquet about possible escape plans, but he practically kills himself arresting Fouquet anyway when the King requests.
Event #3: The King orders D'Artagnan to capture Belle-Isle and its inhabitants, including his two best friends, Porthos and Aramis. D'Artagnan tries to obey the order anyway without injuring his friends. This proves to be impossible, and D'Artagnan resigns rather than fire upon Aramis and Porthos.
Essentially, D'Artagnan is as loyal to the King as he possibly can be without killing his best friends, but this isn't good enough for King Louis, who wants to secure absolute domination over the entire country. Louis points out that D'Artagnan has been accustomed to inferior kings who permit themselves to be led, directed, or manipulated by their advisers. Louis is ushering in a new age, an age in which the King is law and side-stepping is not tolerated. D'Artagnan points out that this will lessen him as the captain of the Musketeers. Rather than be a free-thinker who can argue with his king, D'Artagnan will now be the 17th century's version of a glorified paper-pusher. Louis wants a yes-man, and he seems to get one. D'Artagnan resigns himself to the new terms of the job. Louis is consolidating absolute power with a vengeance (an aspect of The Man in the Iron Mask that is historically accurate).
We thought we'd point out that loyalty, bravery, and kindness don't prevent you from sometimes being a not-so-great guy. D'Artagnan repeatedly shames La Valliere for the suffering she caused both Raoul and Athos, and when he finds her weeping upon their graves and begging for forgiveness, he tells her that "the place of a murderer is not upon the graves of her victims" (30.16). More on La Valliere later. We just wanted to point out here that D'Artagnan is not always perfect.