Except that they aren't medieval and they aren't ruins. They were built to look like ruins. Many of them were constructed in the 18th and 19th centuries by persons with excess wealth and imagination. A little bit of deception for someone's amusement. They refer to them with the term folly.
That brings us to Dissociative Identity Disorder, AKA multiple personalities . . .
I just came across this good review of the DID controversy by Dr. August Piper:
The Persistence of Folly: A Critical Examination of Dissociative Identity Disorder. Part I. The Excesses of an Improbable Concept
Here is an excerpt:
With the recent appearance of several critical articles and books, the concepts of dissociative amnesia and dissociative identity disorder (DID) have suffered some significant wounds (1–5). Between 1993 and 1998, the principal dissociative disorders organization lost nearly one-half of its members (1). In 1998, Dissociation, the journal of the dissociative disorders field, ceased publication. A paper published in 2000 examined the weaknesses in the dissociative amnesia construct (6). Various dissociative disorder units in Canada and the US (for example, in Manitoba, Illinois, Pennsylvania, and Texas) have been closed down. US appellate courts have repeatedly refused to accept dissociative amnesia as a valid entity (6), and several ardent defenders of dissociative disorders faced criminal sanctions, malpractice lawsuits, and other serious legal difficulties.
Nevertheless, despite the significant harm these concepts have wrought in North America, some Canadian and US practitioners continue to support, and practise according to, dissociative disorder concepts (7–9). Further, these North American countries export the concepts. In India, for example, the cinema has influenced the production of dissociative signs (10), and 4 recent papers demonstrate a recurring interest in spreading awareness of DID to other countries (11–14).
and on it goes.
Like the follies built by the idle rich of the romantic period, DID is not simply wrong, it is a fantasy people want to believe and proliferate.