Second Punic War participant Ancient Rome
Background
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 270 BC, when the Greek cities of southern Italy (Magna Graecia) submitted. During this period of Roman expansion, Carthage, with its capital in what is now Tunisia, had come to dominate southern Iberia, much of the coastal regions of North Africa, the Balearic Islands, Corsica, Sardinia and the western half of Sicily. By 264 BC Carthage was the dominant external power on Sicily, 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 First Punic War was the issue of control of the independent Sicilian city state of Messana (modern Messina). In 264 BC Carthage and Rome went to war.The war was fought primarily on Sicily and its surrounding waters; the Romans also unsuccessfully invaded North Africa in 256 BC. It was the longest continuous conflict and the greatest naval war of antiquity, with immense materiel and human losses on both sides. In 241 BC, after 23 years of war, the Carthaginians were defeated. Under the Roman-dictated Treaty of Lutatius Carthage ceded its Sicilian possessions to Rome. Rome exploited Carthage's distraction during the Truceless War against rebellious mercenaries and Libyan subjects to break the peace treaty and annex Carthaginian Sardinia and Corsica in 238 BC. Under the leadership of Hamilcar Barca, Carthage defeated the rebels in 237 BC.
With the suppression of the rebellion, Hamilcar understood that Carthage needed to strengthen its economic and military base if it were to confront Rome again; Carthaginian possessions in Iberia (modern Spain and Portugal) were limited to a handful of prosperous coastal cities in the south and Hamilcar took the army which he had led in the Truceless War to Iberia in 237 BC and carved out a quasi-monarchical, autonomous state in southern and eastern Iberia. This gave Carthage the silver mines, agricultural wealth, manpower, military facilities such as shipyards, and territorial depth to stand up to future Roman demands with confidence. Hamilcar ruled as a viceroy and was succeeded by his son-in-law, Hasdrubal, in 229 BC and then his son, Hannibal, in 221 BC. In 226 BC the Ebro Treaty was agreed with Rome, specifying the Ebro River as the northern boundary of the Carthaginian sphere of influence. At some time during the next six years Rome made a separate agreement with the city of Saguntum, which was situated well south of the Ebro. In 219 BC a Carthaginian army under Hannibal besieged Saguntum, and after eight months captured and sacked it. Rome complained to the Carthaginian government, sending an embassy to its senate with peremptory demands. When these were rejected Rome declared war in spring 218 BC.Since the end of the First Punic War Rome had also been expanding, especially in the area of north Italy either side of the River Po known as Cisalpine Gaul. Roman attempts to establish towns and farms in the region from 232 BC led to repeated wars with the local Gallic tribes, who were finally defeated in 222. In 218 the Romans pushed even further north, establishing two new towns, or "colonies", on the Po and appropriating large areas of the best land. Most of the Gauls resented this intrusion.