Made by Hxseek using the following sources:

• Map from: en:File:Roman Empire 125.svg by ArdadN
• Info from:

(1) The Early Medieval Balkans. A Critical Survey from the Sixth to the Late Twelfth Century. J V A Fine, Jr. Pg 262:

To the south of the Drava, he (King Tomislav)held what we think of modern Croatia, Slavonia, northern and western Bosnia, and the territory along the Dalmatian coast to the mouth of the Cetina river (excluding scattered Byzantine towns)

(2) The Balkans. From Constantinople to Communism. D P Hupchik. Map 3, depicts Croatia to extend approximately to the Drina river.

(3) Shepherds Historical Atlas.