The siege of Drepanum came late in the First Punic War. By the end of the 240s, Drepanum and Lilybaeum were Carthage’s only remaining bases on Sicily. Lilybaeum had been under siege since 250, but since their defeat at Drepanum in 249 the Romans had been without a fleet, making it almost impossible for the Romans to capture either place.
The main problem for Rome was she was financially exhausted after twenty years of war. The public purse would not support the creation of a new fleet. The senate decided to take a gamble, and fund a new fleet privately, on the understanding that they would be paid back after a Roman victory. A new type of ship was chosen, based on one captured earlier in the war, and said by Polybius to be from Rhodes.
News of this new fleet does not appear to have reached Carthage in time for them to react. In the summer of 242 B.C., under the command of the senior consul, L. Lutatius Catulus, the Roman fleet sailed for Sicily. Finding the harbour at Drepanum empty of Punic warships, he landed outside the city, and placed it under siege.
Although the siege was conducted seriously, it was a side issue. The Romans had built their new fleet to win a naval victory. In the spring of 241 B.C. the Carthaginian fleet came out to offer battle and was defeated at the battle of the Aegates Islands. In the aftermath of this defeat, Carthage made peace. Under the terms of that peace, Carthage withdrew from Sicily.