Why did Alexandre Dumas use Greek names for the three musketeers?

Question

In the 1844 novel The Three Musketeers by French novelist Alexandre Dumas there are three musketeers who are named Aramis, Athos, and Porthos.

But they are French. Why did Alexandre Dumas choose Greek names for them?

Answer 1

Dumas based The Three Musketeers very loosely on the fictionalized memoirs of Charles de Batz de Castelmore d’Artagnan (1611–1673), in which:

Celui que j’accostai s’appelloit Portos, & étoit voisin de mon Père de deux ou trois lieuës. Il avoit encore deux Frères dans la Compagnie, dont l’un s’appelloit Athos, & l’autre Aramis.

The man that I had accosted was called Porthos, and he was my father’s neighbour of two or three leagues. He had two brothers† in the company [of musketeers], of whom one was called Athos, and the other Aramis.

_{Gatien de Courtilz de Sandras (1700). Memoires de Monsieur d’Artagnan, p. 14. Cologne: Pierre Marteau.}

_{† “brothers” means “close friends” here.}

All three of these musketeers were from Gascony, and their names are French or Basque:

• “Porthos” was Isaac de Porthau (1617–1712), or in some sources, his brother Jean. The name is French:

  The Porthaus were an ancient family of Béarn, taking their name from one of the old porthaux or portes (small frontier towers resembling the peel-towers of the British Border) with which the French and Spanish Pyrenees were studded.

  _{Gerald Brenan (1899). ‘The Real d’Artagnan’. In Macmillan’s Magazine, volume 80, p. 205.}

  Brenan says that although Dumas kept the name “Porthos” for d’Artagnan’s friend, he based his character on another figure (M. Besmaux) in the Memoires.

• “Athos” was Armand d’Athos (1615–1643). The name is from the village of Athos in Gascony, which may derive from the Basque name Ato. The resemblance to Mount Athos in Greece is coincidental.

• “Aramis” was Henri d’Aramitz (1620–1655? 1674?), who was lord of Aramits in Gascony. The name of the village is Basque, from aran meaning “valley”.

The OP wonders in comments why Dumas did not use the spellings “Porthau” and “Aramitz”, but Dumas was not in a position to do this, as he was working from the Memoires, where the spellings are “Portos” or “Porthos” and “Aramis” respectively. As for the spellings in the Memoires, no-one knows exactly what sources de Sandras drew on for this work, which was written a couple of decades after the death of its subject. Possibly de Sandras had interviewed people who had known d’Artagnan (“il y a plusieurs personnes qui l’ont connu”, p. 2), in which case he would have had to deduce the spellings from the pronunciations, or possibly he had access to documents such as letters that were contemporary with his subject (“je rassemble ici quantité de morceaux que j’ai trouvez parmi ses papiers après sa mort”, p. 2), but if so, these must have been from the mid-17th-century, which was before French spelling was standardized: the Dictionnaire de l'Académie française only began to be published in 1687. We must be careful not to project modern ideas about spelling (that is, that every name has a single correct spelling) back into a period when people did not always spell their own name consistently. In French, the spellings “Portos”, “Porthos”, “Porthau”, and “Porthaux” indicate similar sounds, so 17th-century writers may simply have picked the spelling they liked best, and this may well have been for Latinizing or Graecizing reasons.