 Rome concluded a treaty with Hasbrubal "with the stipulation that neither side should extend its dominion beyond the Ebro, while the Saguntines, situated between the empires of the two peoples, should be preserved in independence".The cities in the northern part of the east coast were concerned about further Carthaginian expansion and allied with Rome to get her protection.This led to the establishment of the River Ebro as the boundary of the spheres of influence of the Carthaginians and the Romans in eastern Hispania.