4. C.AtiliusRegulusSerranus, M. F. M. N., was consul for the first time in B. C. 257, with Cn. Cornelius Blasio, and prosecuted the war against the Carthaginians. He defeated the Carthaginian fleet off the Liparaean islands, though not without considerable loss; obtained possession of the islands of Lipara and Melite, which he laid waste with fire and sword, and received the honour of a naval triumph on his return to Rome (Plb. 1.25 ; Zonar. 8.12; Oros. 4.8; Fasti Capitol.). Regulus was consul a second time in B. C. 250, with L. Manlius Vulso. In this year the Romans gained a brilliant victory at Panormus, under the proconsul Metellus, and thinking that the time had now come to bring the war to a conclusion, they sent the consuls to Sicily with an army of four legions and two hundred ships. Regulus and his colleague undertook the siege of Lilybaeum, the most important possession of the Carthaginians in Sicily; but they were foiled in their attempts to carry the place by storm, and after losing a great number of men, were obliged to turn the siege into a blockade. (Plb. 1.39, 41_48; Zonar. 8.15; Oros. 4.10; Diod. Fragm. xxiv.)

This Regulus is the first Atilius who bears the surname Serranus, which afterwards became the name of a distinct family in the gens. The origin of this name is spoken of under SERRANUS.