The Scarlet Pimpernel
Orczy, Baroness EmmuskaThe novel is set during the Reign of Terror following the start of the French Revolution. The title is the nom de guerre of its hero and protagonist, a chivalrous Englishman who rescues aristocrats before they are sent to the guillotine. Sir Percy Blakeney leads a double life: apparently nothing more than a wealthy fop, but in reality, a formidable swordsman and a quick-thinking master of disguise and escape artist. The band of gentlemen who assist him are the only ones who know of his secret identity. He is known by his symbol, a simple flower, the scarlet pimpernel (Anagallis arvensis).
Orczy's premise of a daring hero who cultivates a secret identity disguised by a meek or ineffectual manner proved enduring. Zorro, Doctor Syn, the Shadow, the Spider, the Phantom, Superman and Batman followed within a few decades, and the trope remains a popular one in serial fiction today. Read by Stan Lee as a boy, the Marvel co-creator called The Scarlet Pimpernel "the first character who could be called a superhero."