The principal objects of the Carthaginians in Spain were to develop the rich silver mines of the land and to engage in commerce. In furtherance of these aims they established a rigorous military system, putting garrisons in the cities, and insisting on tribute in both soldiers and money. In other respects they left both the Phœnician colonies and the native tribes in full enjoyment of their laws and customs, but founded cities of their own on the model of Carthage. They did not attempt a thorough conquest of the peninsula until their difficulties with the rising power of Rome pointed out its desirability. In the middle of the third century B.C., Carthage, which had long been the leading power in the western Mediterranean, came into conflict with Rome in the First Punic War. As a result of this war, which ended in 242 B.C., Rome took the place of Carthage in Sicily. It was then that Hamilcar of the great Barca family of Carthage suggested the more thorough occupation of Spain as a counterpoise to the Roman acquisition of Sicily, in the hope that Carthage might eventually engage with success in a new war with Rome. He at length entered Spain with a Carthaginian army in 236 B.C., having also been granted political powers which were so ample that he became practically independent of direction from Carthage. The conquest was not easy, for while many tribes joined with him, others offered a bitter resistance. Hamilcar achieved vast conquests, built many forts, and is traditionally supposed to have founded the city of Barcelona, which bears his family name. He died in battle, and was succeeded by his son-in-law, Hasdrubal. Hasdrubal followed a policy of conciliation and peace, encouraging his soldiers to marry Iberian women, and himself wedding a Spanish princess. He made his capital at Cartagena, building virtually a new city on the site of an older one. This was the principal military and commercial centre in Spain during the remainder of Carthaginian rule. There the Barcas erected great public buildings and palaces, and ruled the country like kings. Hasdrubal was at length assassinated, leaving his command to Hannibal, the son of Hamilcar. Though less than thirty years of age Hannibal was already an experienced soldier and was also an ardent Carthaginian patriot, bitterly hostile to Rome. The time now seemed ripe for the realization of the ambitions of Hamilcar. [Sidenote: Siege of Saguntum.]