
According to Porphyrogenitus, Serbs formed the original population of those regions from the early 7th century up to 955 AD considering that D.A.I was written a full 2 decades after Bosnia & Dalmatia had been first occupied by Croatia.
De Administrando Imperio is rejected by Catholic and Muslim academics in Bosnia & Croatia, although it is internationally recognized. They reject this work because it so clearly and specifically identifies Bosnia, Hercegovina & Dalmatia as exclusively Serb populated territory that it leaves no room for legitimate debate or questioning.
- Chapter 30
The River Cetina is the border between Serb land & Croatia

[...]
"From Ragusa begins the domain of the Zachlumi (Ζαχλοῦμοι) and stretches along as far as the river Orontius; and on the side of the coast it is neighbour to the Pagani, but on the side of the mountain country it is neighbour to the Croats on the north and to Serbia at the front. From the Orontius begins Pagania and stretches as far as the River Tzentina (Cetina)" [...]

"From the River Tzentina begins the country of Croatia..." (page 145)
- Chapter 32 & 36
The Paganians/Narentans were Serbs
This is a very important point to clarify, as Paganians are constantly being misidentified as undifferentiated Slavs by Croatians pseudo-scholarship. Leo Rabaduchas, mentioned contemporaneously with Caslav Klonimirovic shows that as late as the 10th century, Pagania was populated by Serbs, not Croats...


"These same Pagani are descended from the unbaptised Serbs of the time of that prince who claimed the protection of the Emperor Heraclius. […] The Pagani are thus called because they did not accept baptism at the time when all the other Serbs were baptized. In pagania are the inhabited cities of Mokron, Ostrok, Slavnitza...Kourkira, Melet…another large Island Phara, another large island Bratzis". (chapter 36)

Chapter 32
"After some time these Serbs decided to depart to their homes and the Emperor sent them off but when they crossed the river Danube, they changed their minds and sent a request to the Emperor Heraclius" [...]

"And since what is now Serbia, Pagania, and the so-called country of Zachoulmia and Trebounia and the country of the Kanalites were under dominion of the emperor of the Romans, and since these countries had been made desolate by the Avars (for they had expelled those parts the Romani who now live in Dalmatia and...." (page 154)

Chapter 33: Zahumlje
"The Zahumljani (Захумљани) that now live there are Serbs, from the time of the prince (archont) who fled to emperor Heraclius" (page 162)

"In the territory of the Zachoumlians are the following inhabited cities: Ston (το Σταγνον / to Stagnon), Mokriskik (το Μοκρισκικ), Josli (το Ιοσλε / to Iosle), Galumainik (το Γαλυμαενικ / to Galumaenik), Dobriskik (το Δοβρισκικ / to Dovriskik)"
[...]

Chapter 34: Travunia
"Travunia (Terbounia) and Konavli is one. Its inhabitants originate from unchristened Serbs, who lived there since the archont that fled from unchristened Serbia to Emperor Heraclius and Serb archont Vlastimir [...] "The archonts of Travunia have always been subject to the archont of Serbia" [...] "Populated cities in Travunia and Konavli are: Travunia (ηε Τερβουνια), Vrm (το Ορμος), Risan (τα Ρισενα), Lukavete (το Λουκαβεται), Zetlivi (του Ζετλεβε)." (page 163)