The Battle of Catana took place in the summer of 397 BC. The Greek fleet under Leptines, the brother of Dionysius I of Syracuse, engaged the Carthaginian fleet under Mago near the city of Catana in Sicily. While the Greek army under Dionysius was present near the city of Catana during the battle, the Carthaginian army under Himilco was away in the interior of Sicily, making a detour around the erupting Mount Etna. The Carthaginian fleet crushed the Greek fleet in the battle, leading to the Carthaginian siege of Syracuse later in 397 BC.
Background
Carthage had invaded Sicily in 406 BC in retaliation of Greek raids on Phoenician lands. The expedition, first commanded by Hannibal Mago, and, after the battle of Akragas, by his kinsman Himilco, had managed to capture and sack the cities of Akragas, Gela and Camarina by the summer of 405. These defeats had caused political turmoil in Syracuse, and had ultimately brought Dionysius I of Syracuse to power as tyrant. Himilco and Dionysius signed a peace treaty to end the conflict in 405 BC, which had left Carthage in direct or indirect control of 3/5th of Sicily. The Sicels and the cities of Messina and Leontini were left independent while Dionysius was acknowledged as the ruler of Syracuse by Carthage.
Dionysius in charge
Between 405 BC and 398 BC, Dionysius set about securing his political position and increasing the military might of Syracuse. He broke the treaty in 404 BC by starting a war with the Sicels. While Carthage did nothing, Dionysius was put in a difficult position by a revolt in his army, which managed to besiege Dionysius in Syracuse. Fortune and incompetence of his enemies had helped Dionysius to ultimately emerge triumphant from this crisis. Dionysius then enlarged his territory by conquering and sacking the cities of Naxos and Catana, and annexing Leontini. He hired mercenaries and enlarged his fleet building 200 new ships. The city of Syracuse was fortified, with Dionysius making the island of Ortygia (where the original city of Syracuse stood) into a fortress and encompassing the whole of Epipolae Platue by massive walls. He hired workmen to create new weapons like the catapult and new ships like the quinquereme. In 398 BC, Dionysius attacked the Phoenician city of Motya in Western Sicily with an army of 80,000 infantry and 3,000 cavalry, along with a fleet of 200 warships and 500 transports carrying his supplies and war machines.
The Sicilian Greeks and Sikans under Carthaginian dominion took this opportunity to rebel, and by the time Dionysius besieged Motya, only five cities remained in league (Segesta, Entella, Panormus and Solus among them) with Carthage. Lacking a standing army, Carthage could only send a fleet of 100 triremes under Himilco to Sicily. The city of Motya stands on an island in the middle of a lagoon, so Dionysius had to build a mole to reach the city walls. While the Greeks were thus occupied, Himilco managed to surprise the Greek fleet and trap them on the lagoon north of Motya. Most of the Greek ships were beached, and Himilco had destroyed the transports at anchor near Lilybaeum before sailing to Motya. Dionysius managed to hold the Carthaginian fleet off by catapult fire, while his men built a wooden road of planks on the isthmus north of Motya and dragged 80 triremes to the open sea. Himilco, outnumbered and outmaneuvered, was compelled to sail away. Dionysius then assaulted Motya after the mole was finished, the city fell after fierce resistance, and was thoroughly sacked. After garrisoning the city, Dionysius left 120 ships under his brother Leptines at Eryx, put Segesta under siege and retired to Syracuse for the winter.