The Three Musketeers is a historical fiction and adventure novel written by French author Alexandre Dumas père, originally published in 1884. It tells the story of D'artagnan, who is a young man who dreams of becoming a musketeer, just like his father; he decides to go to Paris, hoping to fulfill his dreams, and on the road he meets three musketeers who go by the names of Athos, Porthos and Aramis.

As he is in a rush to meet with the musketeers' general, Tréville, he manages to insult all three of them and challenges them to a duel in order to solve their dispute. After seeing D'artagnan's potential and his kind and generous soul, as well as his passion for justice, Athos, Porthos and Aramis befriend the young musketeer-to-be, and together, the quartet manages to save the kingdom. In the end, D'artagnan's dream becomes a reality, and he finally joins the king's musketeers.

There are many musketeers in Dumas's popular novel who serve as protectors of the king; they are described as righteous and highly skilled swordsmen and competent combatants who operate under the motto, "Un pour tous, tous pour un (One for all, and all for one)." However, there are only three main musketeers—the aforementioned Athos, Porthos and Aramis—along with the main protagonist D'artagnan, who becomes a musketeer after he proves himself to be a worthy and honorable man.