the map is an indication of what it was when Pliny was alive, it does not reflect the full lands of the illyrians as per their link/mix with celts in austria and slovenia as per halstatt culture..
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proper illyrians are basically what was described by byzantine and venetian scholars in later articles as the rugusans ,( republic of ragusa ) or South Dalmatian illyrians....who , if this map is correct, must have lost coastal south Montenegro by 1000AD.............venetian archives state Montenegro was inhabited by, northern coast where dalmatians, south coast where albanians and the inland was only croats and serbs, bosnians never entered Montenegro.
Bosnians came from one small illyrian tribe called the Poseni , which over time the P became a B