The Roman Republic had been aggressively expanding in the southern Italian mainland for a century and had conquered peninsular Italy south of the Arno River by 272BC, when the Greek cities of southern Italy (Magna Graecia) submitted after the conclusion of the Pyrrhic War. During this period of Roman expansion, Carthage, with its capital in what is now Tunisia, had come to dominate southern Spain, much of the coastal regions of North Africa, the Balearic Islands, Corsica, Sardinia, and the western half of Sicily. By 264BC, Carthage was the dominant external power on the island, and Carthage and Rome were the preeminent powers in the western Mediterranean. Relationships were good, the two states had several times declared their mutual friendship and there were strong commercial links. According to the classicist Richard Miles, Rome's expansionary attitude after southern Italy came under its control combined with Carthage's proprietary approach to Sicily caused the two powers to stumble into war more by accident than design. The immediate cause of the war was the issue of control of the independent Sicilian city state of Messana (modern Messina). In 264BC Carthage and Rome went to war, starting the First Punic War.