It's always interesting to see how shifts in philosophical thinking occur in waves across interconnected cultural traditions. Europe always had a diverse set of attitudes toward non-normative sexuality. But you can see specific concepts take hold and spread, either integrating with, or replacing, the existing local attitudes. These sorts of shifts are easier to see in more recent centuries. In medieval and early modern sources, the divide between the intellectual tradition of classical philosophy and the everyday experieces and reactions on the streets and in the courts can mask both the diversity of local tradition and the spread of intellectual theories. (A good example is the Zimmern Chronicle, where the author considers a number of potential "causes" for women's same-sex desire, some of them rooted in international philosophical traditions, some expressed in everyday social reactions.) In reviewing this series of articles on the rise of sexology in various countries, we can see in more detail how ideas about sexuality and gender spread and were integrated into existing understandings.
Beccalossi, Chiara. 2009. “The Origin of Italian Sexological Studies: Female Sexual Inversion, ca. 1870-1900” in Journal of the History of Sexuality 18:1 pp.103-120
This article covers much of the same territory as Bauer’s article from the same volume (Bauer 2009) except from a specifically Italian perspective. The concept of “sexual inversion” entered Italian medical literature in 1878, but female same-sex desire was a familiar concept already and was associated with excessive sexual longing, female masculinity, and certain women-only environments. The article looks at how those concepts were interpreted during the devopment of sexology as a study at the end of the 19th century.
A psychological approach to same-sex desire was already present in the late 18th century work of Vencenzo Chiarugi, who viewed desire between women as a type of mania, one of the three types of mental illness he identified (mania, melancholy, and amentia). Melancholy, he described as a restriction in judgment or the ability to reason. He offered an example interpreted from Hippocrates called “Scythian melancholia” whereby Scythian men, due to riding horseback without stirrups, became functional eunuchs and therefore take on feminine roles when the find themselves unable to perform sexually as men. Beccalossi suggests that this is parallel in some ways to the later concept of “sexual inversion”, though that seems to be stretching the concept.
The article continues examining how psychological concepts and categories were applied specifically to sexuality. A view of homosexuality as a type of monomania was replaced with a focus on the concept of “moral insanity” in which an emotional crisis, sometimes accompanied by a physical abnormality, precipitated anti-social sexual behavior.
Italian medical literature of the mid 19th century (e.g., Ferdinando Tonini) still sometimes linked female same-sex desire to an enlarged clitoris, as a contributing factor if not necessarily a causal factor. In general, the theory was that some sort of sexual excess--of physiology or desire--underlay desire between women. But he also associated female same-sex desire with urban centers, women-only institutions (convents, colleges, or prisons), lack of maternal feeling, and masculine appearance.
Legal reforms in the 19th century (in the aftermath of French occupation and legal influences) addressed crimes of female sexuality but also attempted to equalize how the law treated men and women, at least in certain areas. Certain asymmetries were unavoidable, as with the legal control of prostitution, and women’s lack of political power. The introduction in Italy of Napoleonic law codes decriminalized male homosexuality except in cases of violence, and rarely mentioned sex between women at all.
The introduction late in the century of the psychological concept of sexual inversion covered two distinct issues: self-identification with the opposite sex from one’s physiology (what would today be considered transgender identity) and sexual desire for members of the same sex. Authors such as Tamassia considered the first to be the element that made sexual inversion a type of mental illness, and not simply same-sex erotic desire. He considered that most human passions and tendencies derived from sexual instinct, and therefore a disorder of that instinct resulted in mental illness, and frequently to criminal activity.
As in other countries, theories were developed out of case studies which were drawn from individuals already under medical treatment for insanity or mental disorder, thus leading to the belief in an association between sexual inversion and mental illness. Once such theories had developed, psychiatrists studying sexual disorders looked specifically for characteristics (such as masculine behavior in women) that they already believed were characteristic features of the condition.
In the 1890s, Italian sexological theorists became interested in classifying types of sexual inverts in terms of their relationships, partners, and life context. From this, they created two specific stereotypes of female inversion: the “tribade-prostitute” based on studies of women in the criminal justice system for crimes of sexual disorder, and the “flame” based on same-sex relations in gender-segregated institutions such as girls’ schools. Theories of social criminality were interwoven with sexual theory, such as the belief that women became prostitutes due to an inherent disposition rather than due to poverty or, alternately, that prostitutes turned to lesbianism in response to the brutality of their male customers.
The interest in the “flame” stereotype of lesbian activity had its roots in concerns in religious institutions regarding “special friendships” between nuns, but was extended to concerns about the passionate friendships that developed between girls in gender-segregated school environments. Although “flame” relationships might be confined to expressions of emotional attachment, they frequently included a physical component, even if simply an admiration of the partner’s beauty. Psychiatrists considered these “flames” to be a transitory state and only tangentially related to sexual inversion. They were to be controlled and discouraged but considered a temporary substitute for “normal” love.
In summary, beginning around 1880, there was a proliferation of publications on sexual inversion in Italian, with a special interest in female homosexuality. This can be attributed (in retrospect) to a voyeuristic interest on the part of male physicians, but such studies also served a social purpose of framing approved female sexuality in terms of procreation. At the same time, there was a shift away from studying female homosexuality as an abnormal phenomenon to considering it as a normal, but transient situational experience, albeit one that posed a potential threat to “innocent” women if taken to extremes.