The fall of Liburnian domination in the Adriatic Sea and their final retreat to their ethnic region (Liburnia) were caused by the military and political activities of Dionysius the Elder of Syracuse.
In a 891 deed mentioned as Liburnia, it became the centre of the Upper Carinthian counts in the mediæval Lurngau, who resided at Hohenburg Castle.
Istria was annexed by the Franks during the reign of Pepin the Short in 789, But Liburnia became part of the State of Croatia.
Their territory began after Liburnian Scardona (Skradin), spreading in small region directly to the south of Liburnia, and border ran roughly through the middle of the peninsula which Roman sources called Hyllus.
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In Liburnia, centres such as Nedinium (Nadin), Asseria (Podgrađe, near Benkovac), Iader (Zadar) continued to exist in Roman times, and the Liburnians retained their ethnic distinctiveness under Rome, while the same did not occur on the neighbouring Hyllus Peninsula.