The string of Roman naval victories, such as Mylae and Ecnomus, have given the Romans the confidence to make a direct attack on the Carthaginian stronghold of Lilybaeum, governed by Himilco.
The city is blockaded by a fleet commanded by the year's consuls, Publius Claudius Pulcher and Lucius Junius Paullus.
However, despite the acquired Roman naval experience, the Carthaginians are still superior in open sea maneuvering.
A small squadron led by a commander named Hannibal, son of Hamilcar, manages to break the siege in broad daylight and deliver supplies to the garrison of Lilybaeum.
In the night, Hannibal leaves he city carrying the useless cavalry horses and sails to the harbor of Drepana, before the Romans knew what was happening.
The success of the enterprise is so stunning that the Carthaginians repeat it several times, annulling the whole effect of the siege, since the garrison is being fed and kept in contact with Carthage.
Shortly after, a brave sailor, identified as Hannibal the Rhodian, openly defies the Roman fleet by sailing around the fleet in order to spy on the town and relay the news of the goings on inside of Lilybaeum to the Carthaginian Senate and the Carthaginian commander at the battle, Ad Herbal.
Pulcher, the senior consul, now decides to launch a surprise attack on the harbor of Drepana, where the defiant ships are garrisoned.
The fleet sails north from Lilybaeum in a moonless night.
Carthaginian scouts do not spot the Roman ships but low visibility conditions compromise the battle formation.
When they reach Drepana at sunrise, the fleet is scattered in a long, disorganized line with Pulcher's ship in the rear.
Punic scouts see the clumsy approach and the advantage of surprise is lost.
Ad Herbal orders the evacuation of Drepana before the blockade is unavoidable.
Carthage's ships thus sail out of Drepana, passing south of the city and around two small islands in the coast to the open sea.
Seeing the plan of a surprise attack fail, Pulcher orders his fleet to regroup into battle formation, but by this time the coast of Sicily is at his back and the Punic fleet ready for battle at his front.
Herbal sees a chance for victory and attacks, ordering his right flank to attack the rearmost Roman ships.
The result is an utter Roman defeat, with almost all ships commanded by Pulcher sunk.
Pulcher manages to escape and returned to Rome in shame, where he faces charges of treason.
Unlike the Carthaginians, Romans do not execute generals for incompetence.
He is convicted and sentenced to exile, with his political career finished.
In the same year, Hamilcar Barca leads a successful campaign in Sicily and a storm destroys the other half of the Roman fleet, commanded by consul Junius Paullus.
The situation is so desperate that Aulus Atilius Calatinus is appointed dictator and sent to the island to control the land warfare.
The Drepana defeat so demoralizes the Romans that they will wait seven years before building another fleet.
The Carthaginians have gained command of the sea after their victory in the Battle of Drepanum, but they only hold two cities in Sicily: Drepanum and …