This article title should be Borna of Dalmatia and Liburnia, because that was his title (not croatia).

"croatia" or "Croatia"?? Illiteracy or ...? Anyway, Borna had various titles, depending of sources, but he was ruler of the Principality or Duchy of Croatia, like his predecessors and successors.

Borna ruled the Duchy (or Principality) of Croatia (the littoral part of lands inhabited by Croats), not the Duchy of Dalmatia or Liburnia, and was Frankish vassal. On the contrary, Dalmatian cities were part of Byzantine Empire. Liburnia didn't exist any more. See corresponding articles. --Silverije