Salona and Iader with their complex story from ancient times, have given archeologists ideal material for studying their evolution. Salona has gone through a thorough process of urbanization, from the Illyric to the Greek settlement, from the Roman convent and colony and finally to the capital of the Roman province of Dalmatia. With the arrival of the Greeks in the 2nd century BC and the spread of their influence, Salona and other cities on the East Adriatic coast had started to gain elements of ancient urbanisation. When the Romans ruled the Illyric in the 1st Century BC, Salona after participating in the military quests between Caesar and Pompeius, took the side of Caesar and was eventually named a colony, thus marking the beginning of its prosperous era. Thanks to the Pax Romana that was proclaimed in the Roman Empire at the time, the city started spreading its borders and also gained some of the key urban elements that made it so recognisable. Whilst on the example of Salona we can clearly follow all the stages of the city’s urbanisation from an Illyric settlement to the Roman colony, in Zadar that process took place at once. Zadar is located on a small peninsula where it managed to evolve from an Illyric settlement to a Roman Colony. Gaining the title of a colony matches perfectly with the golden era of this city in which all the distinguishable elements were built. The ancient photo of the city matches with the classical Roman urban idea as we can clearly see the orthogonal communications and the city square is located on the intersection of the cardio maximus and decumanus maximus. Salona and Iader at the peak of their power had all the necessary urban elements ranging from squares, thermae and aqueducts, emporiums to necropoli. The end of the late ancient and early medieval stage left little in Salona, however most of the city elements can still be distinguished. Zadar on the other hand still boasts the largest and most well preserved Roman square on the eastern Adriatic coast. One must reach out for technical reconstruction, as the monuments are not preserved well enough in order to get a full picture of these two magnificent cities. I believe the Early Principate era of Roman history which was presented in this thesis is the most important historical period for these two cities as it has yielded synonyms that we still use today when we mention the names Salona or Iader.