Nobility vs. The Masses
When it was first published, The Scarlet Pimpernel was considered classist by critics because it so clearly takes the side of the upper-crust nobles in The French Revolution. Indeed, a key theme that emerges in Orczy's novel is an innate tie between nobility and heroism -- the idea that all the qualities of a grand adventure hero, namely charisma, beauty, elegance, ingenuity, and fashion, are all natural qualities of the noble class. This is, of course, quite obviously wrong (as any look at the actual history that preceded the French Revolution will show), but Orczy, a baroness herself, makes no bones about her allegiance. In order to create sympathy for the nobility, however, she must create the sense that the masses are bloodthirsty enough to kill indiscriminately.
Guilt vs. Redemption
What makes a hero? In Orczy's novel, it's a question often motivated by guilt. Lady Blakeney, for instance, knows that her husband hates her because he thinks she condemned the St. Cyrs to die maliciously; thus she is determined to atone for the sin he thinks she's committed. Meanwhile, Percy seems to feel at least some guilt for deceiving his wife about his identity as the Pimpernel, and enough that he cannot reveal his identity even when she confesses her own internal guilt and turmoil over the St. Cyr incident. Marguerite, meanwhile, has to struggle over the guilt that comes with making the choice between saving her brother, Armand, or saving the Scarlet Pimpernel, who she considers "noble and just." When, of course, it is revealed that the Pimpernel is in fact, her husband, Lady Blakeney is left guilty no matter who she chooses to save. The plot machinations, however, save her from making a choice in the end.
Disguise
The entire scheme of the plot depends on disguise, as The Scarlet Pimpernel wins not through brawn, but rather through cunning and trickery. It's important to remember that given the political context of the novel, the Pimpernel cannot fight fairly. He will be killed by the guillotine if he is merely arrested. Thus disguise as a way of concealing nobility becomes a crucial theme in the novel -- indeed, the Scarlet Pimpernel takes the disguise of people who would be in the masses, including peasants, old hags, old Jews, etc. in order to save the nobility. He is very much a Robin Hood intent on saving the rich, as bizarre as that sounds.
The Scarlet Pimpernel
The flower known as the "the Scarlet Pimpernel" is, according to the narrator, "the name of a humble English wayside flower; but it is also the name chosen to hide the identity of the best and bravest man in all the world." The flower, then, which has become Percy's moniker symbolizes all his best qualities -- his English charm, his humble origins, and his innate humility as a hero that expects no reward for his deeds. Perhaps the most admirable thing about Percy is that he's willing to appear stupid, even buffoonish, in order to secretly continue his missions as the Pimpernel. Indeed, behind a deceptively humble front dwells a hero.
Dual Identities
There is an odd dynamic between England and France that dominates the novel -- the former is depicted as a land of justice and simplicity and order and propriety, whereas the latter is vulnerable to the impulsive rage of mobs and sacrificial violence. As a result, then, Marguerite/Lady Blakeney comes to serve as the perfect symbol of this schism. As Marguerite, she caused the condemnation of the St. Cyr family simply through a misspoken denunciation. Upon marrying Percy Blakeney, she maintains her French casualness -- her haughty charm, but her innate ability to hurt people without thinking. Through the course of the novel, she turns more and more English, evolving gradually into the true Lady Blakeney, who stands by her husband, humble and deferential.
Loyalty
Loyalty becomes a crucial determinant of a person's inherent goodness. Chauvelin maintains his group of loyal henchmen, but their loyalty is based solely on rank, and not to his character. At the end, this superficial loyalty leads to the escape of the fugitives, as Chauvelin's soldiers begrudgingly adhere to his strict instructions, knowing they're letting the prisoners go free -- and yet do not let him know. Meanwhile, Percy's followers put themselves in extreme dangers for the sake of the Pimpernel's cause, because they truly believe in their leader and the plight of the nobility.
Pretension
For all the cult of nobility that surrounds Orczy's novel, she puts a premium on humility. Any character that shows the slightest bit of arrogance or pretension is taught the lesson of humility by the end of the novel. In that, perhaps, Orczy is not so much vindicating nobility as much as instructing a new persona for the "brave, just noble" -- one who fights for the right causes, for humanity instead of riches.
