This question prompted a very similar one in my head; the term Burgundian means, at least where I live, an enjoyer of life. What was so Burgundian about the Burgundians?
I’m going to go ahead and post my response here rather than the original question cited by American_Graffiti because my answer is not about the semantics of the word “Bohemianism”, which is very much an arbitrary social signifier that has little to do with the country of Bohemia itself and was effectively discussed by Algernon_Asimov. Instead I want to designate what came to constitute “Bohemian” behavior and why it might be applied to different forms of writing across the 19th and 20th century.
TL:DR definition of Bohemianism: Bohemianism was initially established in reference to impoverished artists living in the Latin Quarter of mid-19th century Industrial Paris. It is predicated on the notion of living “outside” of society in a way that is define directly against the socio-economic norms of the period, usually a middle-class-bourgeoisie type construct, hence the labeling of numerous later counter culture movements like Hippies and Beats as similarly “Bohemian”. This performative “life on the fringe of society” is at the core of what defines Bohemian behavior, but there is also an emphasis on voicing criticisms of mainstream lifestyle through art, music, or literature. Accordingly there is a history of works that either attack popular society or explore the benefits/experience of living outside of it being labelled or self-identifying as "Bohemian", such as Miller’s Tropic of Cancer or Kerouac’s On the Road.
For further detail, I've pulled a handful of extracts (grouped by topic) from a graduate-level paper I wrote for Professor Robert Holton, a senior academic in American literary studies and one of the foremost experts on Bohemianism. I'm aware AskHistorians usually disproves of quoted responses but I figure since its my own work, I've provided context, and it will never be published, an exception could be made. My paper examined the roots of Bohemianism within 19th century industrial Paris through the life and works of two authors fundamental in establishing it in popular consciousness, and was well received.
The first author is Henri Murger, a relatively unremarkable writer save for his 1851 publication of La Vie de Boheme, which profiled the lives of his fellow Parisian artists who lived in abject poverty. A self-identified Bohemian himself, Murger’s collection was almost single-handedly responsible for introducing the idea of Bohemian behavior to the public, and formed the basis for Puccini’s hugely successful 1896 Opera La Boheme. It’s important to note that Murger hated being poor and was writing La Vie in the hopes of making money.
The second is Charles Baudelaire, a poet who lived alongside Murger in the squalor of mid-19th century Paris and wrote about the individual’s struggle to reconcile himself to the urban environment, amongst a myriad of other subjects. Baudelaire is now a titan of French literature, but during his lifetime he was utterly impoverished, and his life and art helped to crystalize what Murger had defined in his novel. Unlike Murger, Baudelaire embraced this poverty and pariah-status willingly, and made it central to his artistic process.
Disclaimer: These essay extracts are very literary in nature as I’m an English scholar. That said, the social history/causality I present, while general, is accurate. Furthermore I’m not nearly as Marxist as this essay may suggest, but almost all of the work on Bohemianism necessarily involves some Marxist thought due to the huge importance Bohemian authors place on class-consciousness and a self-identification with the underclass/lumpenproletariat.
Introduction:
"An inevitable byproduct of urban anonymity is a search for that which is authentic, produced by the sensation of being a single consciousness in a vast tableau of voices, thoughts, and feelings. With the industrial revolution of the early 19th century, city populations rose to unprecedented levels and pushed this dilemma of defining oneself against the miasma of the crowd to the cultural fore. Young artists in mid 19th century Paris reacted to this quest for authenticity by delving into the city’s cafes and garrets in an effort to find a means of creation uninhibited by the pressures of a country coming to grips with modernity. This loosely defined conglomerate of impoverished yet youthful artists became known as Bohemia, and took shape in opposition to the middle-class bourgeois lifestyle that was also being established at the time. This essay will contrast two artists from the initial wave of Parisian Bohemians, active between 1840-1860, in order to explore the twofold contribution early Bohemia made to the world of literature. The first is Henri Murger, whose work defined Bohemianism for a wider public and thus produced the social construct of Bohemia that would ensure its continued relevance to later artists. Second is the poet Charles Baudelaire, whose writing facilitated an ideological shift towards the autonomous production of art. Through their lives, views, and works, these men embody the respective social and artistic facets of early Bohemianism."
On the Causes of Bohemianism:
"Paris became the first truly modern 19th century city in its intersection of political, artistic, and industrial production, and one of the most significant byproducts of this was a localized sense of class-consciousness fundamental to Bohemia’s establishment, evidenced in Murger’s statement that, “Bohemia only exists, and is only possible, in Paris”. With money replacing hereditary titles as the primary indicator of social status, there arose a conception of a moneyed bourgeoisie that, as they grew in cultural and financial power, aligned notions of social distinction in opposition to the proletariat underclass (Chambers 104). Within Paris intellectual activity had always been closely related to politics, and the gradual rise in political power of the Bourgeois class following the July Revolution meant that it was effectively, “capable of imposing its own form of organization on national life” (Seigal 22). Nowhere did this become more apparent than in the changing perception of art during the period."
"For contemporary artists and writers this was evidenced most clearly in the aristocratic patronage system being replaced by the open market. The bourgeois influence on artistic sensibilities created a movement towards what Pierre Bourdieu terms an “industrialized” approach to literature that emphasized the influence of the market both directly, in relation an artist’s earnings, and indirectly, via new jobs in journalism and publishing (Bourdieau 49). At the time this was construed as both good and bad, with many voicing concerns that the narrow demands of commerce, which measures value by profit, would debase artistic achievement and imagination; while others suggested that freedom from personal subjugation would see the artist act as a voice of the collective people rather than a singular retainer (Seigal 14-15). Thus in being introduced to the market, art simultaneously came to be evaluated based upon its monetary earnings while individual artists were provided an unprecedented degree of independence. In many ways this dualism acts as an analogy to Murger and Baudelaire’s different interpretations of Bohemia’s relationship with art. Murger pursues financial success and identifies Bohemia as a means to achieve this, whereas Baudelaire’s work uses Bohemia to realize the full potential of this newfound individual autonomy in the face of industrialized artistic sensibility."
"To summarize, bourgeois sensibilities had come to be seen as culturally authoritative, the underclass of Paris was its social opposition, and many bourgeois youth were without money or jobs and searching for an artistic outlet. Thus Bohemianism, the practice of young would-be artists appropriating underclass lifestyles in order to develop artistic sensibilities outside those upheld by the bourgeois, acted as a sort of release from these societal pressures."
The first attested mention of Bohemians as wandering artists can be traced back to a French novel called Les Bohémiens (literally, the Bohemians) which was published in… 1790. Apparently, it is completely independent from the later 19th-century attestations of the word in this meaning, given that the book sank into oblivion. It was rediscovered quite recently by Robert Darnton, who has written an interesting article about it, Finding a Lost Prince of Bohemia (I know that it is available on the Internet as a pdf file on an academic site — it is full of interesting details on the life of disgruntled and minor French intellectuals and libellists shortly before the Revolution, and the author of the aforementioned novel has a very interesting story).