The idea that Slovenes, in spite of their Slavic vernacular, were not descended from a medieval Slavic influx but were autochthonous to their area of settlement was proposed in the 1830s by the speculative antiquarian Jurij Venelin; he traced the present-day population back to the tribe of the Veneti, whose name was associated not only with the nearby Veneto region and the city of Venice, but also with the Wends, a West-Slavic tribe (whose name, in turn, was stilll applied to the Lusatian Sorbs at the time). The Styrian-based priest Davorin Trstenjak (1817–1890) picked up the idea and amplified it to assert that the Slovenians were not only descendants of the Veneti but also that as such they were the most ancient indigenous people of Europe. These speculations were demolished by the celebrated and authoritative Slavic philologist Jan Baudouin de Courtenay, and eventually retracted by Trstenjak himself. Even so, attempts to prove an ancient autochtonous nature of Slavic language communities continued: in 1890s, Ivan Topolovšek (1851–1921) attempted to prove a family link with Basque, and in the opening years of the new century Davorin Žunkovič (1858–1940) theorized that Etruscans had been Slavs and that Germanic runes had been a Slavic script. While such theories gained no scientific credence, they maintained a certain currency in non-academic circles, thanks to pro-Yugoslavian journalists like Henrik Tuma (1858–1935).

The Yugoslav kingdom and its socialist successor republic were uncongenial to such speculations, but in the 1960s two autochthonist theories appeared: Stanko Dimnik (1891–1980) argued for Celtic-Slovenian links, and Franc Jeza (1916–1984) suggested that Slovenian was related to Old Norse, claiming that Slovenians (of Vandal-Germanic stock) had reached their present-day territory 2000 years ago from Scandinavia. The political overtones were obvious: Jeza was an anti-Communist and anti-Yugoslavist political émigré in Trieste trying to establish a non-Slavic ethnic particularism for his nationality and advocating the dissolution of Yugoslavia, and his pseudoscience supported Slovenian exceptionalism amongst other (“Slavic”) Yugoslavian nations. Dimnik’s and Jeza’s views remained on the crank fringe at the time, but the need for a non-Yugoslav ethnic particularism was served subsequently by a revival now known as the Venetic Theory.

The post-Communist and postmodernist climate of the 20th century’s closing decades was propitious to the revival of speculative or counterfactual nationalist myths, provided they served the new ethnic essentialism that was fostered  politically in the post-Communist successor states. Many intellectuals and academics, too, tried to distance Slovenia from the other Yugoslav successor states and their perceived ethnotypes, and were sympathetic to, or connived with, a discourse of de-Balkanizing and de-Slavicizing Slovenia.

In a book released in 1984, Anton Berlot (1897–1986) and Ivan Rebec (1908–1990) revived the Etruscan-Slavic connection, while as early as 1981, Jožko Šavli (1943–2011), based in Italy, had been publishing essays about the possible connections between ancient Veneti and contemporary Slovenians; these appeared in the Vienna newspaper Glas Korotana (“The voice of Carinthia”, edited by the Austria-based Slovenian priest Ivan Tomažič). These fringe publications went mainstream with the interventions of Matej Bor (1913–1993), acclaimed academic, renowned partisan poet and playwright. Bor, Šavli and Tomažič established themselves as the leading “Venetologists” and published a German-language book Unsere Vorfahren – Die Veneter (1988), subsequently translated into Slovenian as Veneti – naši davni predniki (1989).

Rife with wayward pseudo-etymologies and untenable speculative projections, their Venetic Theory revived old pre-scientific practices and imputed all sorts of social and cultural features to the obscure “ancestral” tribe, always flattering contemporary Slovenian exceptionalism, vanity or nationalism. Conversely, the scientifically established Slavic origin of the Slovenians was presented as a conspiracy entirely fabricated by 19th-century German-nationalist historians and uncritically adopted by the Yugoslavian regime. A similar mode of arguing is noticeable among right-wing advocates of the Turanian theory in post-1989 Hungary: established academic consensus is exposed to extreme, conspiracy-suspicious scepticism while speculative ethno-chauvinist alternatives are embraced with uncritical credulity. By a similar dynamics, again, a pseudoscientific theory came into vogue in certain Croatian and Serbian circles claiming not a Slavic but an ancient Iranian descent. For its part, the Venetic theory did not shrink from making ancient India proto-“Wendic” by cheerfully re-spelling it as Vindia.

While the Venetic Theory ultimately derived such credence as it could command from the lexical similarities between ethnonyms like Veneti, Wendi, Winidi, Venedi, Enetoi, etc., the Iranian theory rests on analogous ethnonymical analogy-hunting for Croatians (Horoathos, Harahvati, etc. and Serbi, etc.). Such theories thrived in the tensions of the Yugoslavian dissolution. The Venetic Theory maintained credence in certain political circles and was boosted by the anti-Communist diaspora united in the Svetovni slovenski kongres (Slovenian World Congress). When the Bor/Šavli/Tomažič book was published in an English version, it adapted its outreach to the prevailing political wind and was entitled Veneti – First builders of European community (1996). Today, there are around 40 highly dedicated researchers methodologically close to the Venetic Theory, a notable percentage of whom live outside Slovenia. Many more enthusiasts have joined their ranks on Web discussion forums; its chauvinistic and traditionalist tenets and implications find favour especially among the right and far right, where populist anti-intellectualism makes it easy to dimiss academic consensus as the conformism of a “self-appointed elite”. Academics have debunked the Venetic Theory, but its ideological appeal lies beyond the reach of scientific falsification. Not even the country’s state institutions are entirely immune to it: the “national” symbols on Slovenian passports and identity cards prominently include the “Venetic horse”.