The Illyrian hypothesis was advanced by Franjo Rački (1828-1894). A Roman Catholic priest and politician, Rački "promoted the merging of Dalmatia with Croatia ruled by the ban, he wrote discussions about the Croatian nature of Srijem and Rijeka, but he spent most energy on analyzing the relationships between Croatia and Hungary, fighting against the Hungarian expansionism," says his Wikipedia entry.
(As a side note, few today question the "Croatness" of Dalmatia or Rijeka and Istria in general, but in the XIX century these were very much in dispute. Istria was claimed by Italy, as was a lot of Dalmatia, and the dialects spoken there even today sound nothing like the Slovenian-related speech of the region around Zagreb. For "Srijem", see Syrmia/Srem. The only time in history this area was a part of Croatia was 1941-1944.)
Rački also originated the "Bogomil hypothesis," claiming that the Christianity of medieval Bosnia was a heresy that originated in Bulgaria, and had nothing to do with Serbian Orthodoxy. Croat politicians have used this hypothesis to argue that the inhabitants of Bosnia are really apostate Catholics (and hence, Croats). Similarly, conventional wisdom among the Bosnian Muslims is that the "Bogomils" all converted to Islam and became the "Bosniaks" of today, while those who identify as Serbs and Croats are interlopers.
There's а gap in that theory one could drive a carrier battlegroup through: the Ottomans would have considered the so-called "Bogomils" just as Christian as the Orthodox and the Catholics. Therefore, as "people of the Book," they would have been permitted to keep their faith. There are other Christian churches in the East, once persecuted by the Byzantines, that survived under Islamic rule: e.g. Coptic, Maronite, Chaldaean. Yet there are no "Bogomils" in Bosnia. Zero, zip, zilch, nada, not a single one remaining. Bosnia must be the only Ottoman province in which a Christian church simply vanished like it never existed. Strange, is it not?
About a week or so ago, I read a short tidbit in a Bosnian newspaper about the shocking results of genetic research by a Swiss institute IGENEA, indicating that only 20% of Albanians has Illyrian DNA, while it was actually present in 40% or so of Bosnians!
As soon as I returned, I searched for any sign of independent confirmation. What I found suggests that the revelation came as a side effect of research done to settle the issue of Macedonians' (FYROM) genetic origin. Digging some more, I found the following post in the "Antic macedonians" thread of an IGENEA forum:
IGENEA spokeswoman Inma Pazos has made it clear several times that "our numbers in statistics are an average from more than 150 genetic studies published in Science, Nature or AJHG" and that they were not contacted by the journalist who wrote the story. She also appealed that politics should be kept out of the thread or it would be locked. Fat chance - 90% of the thread's content was in the form of "Hahaha, stupid [insert name of ethnic group here], you are wrong!", and that's putting it politely.
Also, this particular thread does not cite any figures about Bosnia at all - Pazos mentions only Bulgaria, Greece, Albania and Macedonia (FYROM). So I'm not sure where the whole "40% of Bosnians have Illyrian roots" came from. Also, the Illyrian percentage in Albania is listed as 30%, not 20% as cited in most articles.
I've thought for a while that it would be nice to do some genetic testing in the Balkans, on fairly large samples of the population, to put an end to a lot of baseless, politically driven speculation. Romantic nationalism was all the rage in the 19th century, with everyone trying to claim ancient origins. Sure, that was easy for the Germans, but all of a sudden people claimed they were Goths, Gauls, Illyrians...
In fact, the "Illyrian movement" was the name adopted by the Croatian activists of the early 1800s. But unlike these activists, who saw similarities between Serbs, Croats and Slovenes and even went so far as to argue that they shared a language, Rački's contemporary and fellow politician Ante Starčević advanced the idea of Croats as a distinct and superior volk in the late 1860s. This idea eventually triumphed; modern notions of Croatian identity are almost entirely in line with Starčević's work.
Would disproving Rački's theories right any of the numerous wrongs perpetrated by chauvinists who have subscribed to them? Unlikely. But it could at least prevent their further use as "historical" arguments, and that by itself is a step in the right direction. So, let's see some actual science at work - more DNA studies, more actual historiography and history - while the theories of Franjo Rački ought to be retired where they belong, alongside the Piltdown Man and the Ptolemaic theory.