After this the land war on Sicily reached a stalemate as the Carthaginians focused on defending their well-fortified towns and cities; these were mostly on the coast and so could be supplied and reinforced without the Romans being able to use their superior army to interfere. The focus of the war shifted to the sea, where the Romans had little experience; on the few occasions they had previously felt the need for a naval presence they had usually relied on small squadrons provided by their Latin or Greek allies. The Romans built a navy to challenge Carthage's, and using the inflicted a major defeat at the Battle of Mylae in 260BCE. A Carthaginian base on Corsica was seized, but an attack on Sardinia was repulsed; the base on Corsica the Romans had seized was then lost. In 258BCE a Roman fleet heavily defeated a smaller Carthaginian fleet at the Battle of Sulci off the western coast of Sardinia.