Are The Three Musketeers fictional

Answer 1

The story itself that was created by Alexandre Dumas was fictionalised. However Alexandre Dumas put such historical content in it (Thirty years war, the rise of Cardinal Richelieu, etc), that it is seen as a historical book. The Musketeers Athos, Porthos, Aramis, and d'Artagnan were real men, but Alexandre Dumas highly fictionalised all of their characters... especially that of Monsieur d'Artagnan.

So to answer your question. Yes the books were highly fictional and no because even though the book came from the writers imagination... the characters were all real men and women.