Roman influence on the eastern Adratic coast between the first Illyrian war and the time of Caesar's proconsulship in Illyricum is complex and varies according to the area and century in question. The beginning of that period was the time when the Roman Republic grew beyond the borders of the Italian Peninsula. During the Roman wars against the Greeks in the 3rd century BC, the strategic importance of the Adriatic became evident, and Romans soon started leading campains on its eastern part in order to secure peaceful Roman trade on numerous coastal routes. However, many heterogenous groups of people called Illyrians lived on the eastern Adriatic coast, who were reluctant to embrace the emerging power, and so Roman Republic first waged wars against the southern Illyrians between 229 and 168 BC but soon started leading campaigns on the northern Adriatic as well, most significantly against the Histri and the Delmatae. Nontheless, there is limited information about the Roman involvement on the eastern Adriatic coast. Greek and Roman written sources are relatively scarce, and, at times, unreliable, and should be studied together with archaeological findings. It took two centuries of waging wars on this side of the Adriatic for Rome to finally incorporate it in the Roman Repulic as the province Illyricum, however, it is still unclear when that happened. By the beginning of the 1st century AD Illyricum was already a Roman province, and romanization began to take root. First the coastal area embraced the Roman culture since the upper class realized how benefitial making peace with Romans was. Its culture then spreaded from the coast inwards, because the maritime people interacted with the Romans as early as the 3rd century BC, sometimes waging wars against each other, and sometimes collaborating for mutual benefit.