I had been aware that female companions (be they wives, sweethearts, or lets say more 'transactional' forms of relationships) of soldiers had been an immutable part of military life in this era and indeed almost every era before it since the dawn of warfare, but finding out the daughter of an aristocrat in Regency Britain had a battlefield amputation still honestly shocked me. It's the sort of thing where unless you specifically heard about cases like this, if you saw it portrayed in a film you would think "There's no way this was real.". Jane Austen could've had a character like her in one of her novels, and it'd be entirely authentic.