The battle of Lautulae (315 BC) was the second major Samnite victory during the Second Samnite War, but one that didn't result in any long term advantages.
The first phase of the war had ended in a truce, but in 316 the Romans attacked Saticula, a Samnite ally, and the war resumed. The city eventually fell to the Romans in 315, although at about the same time the Samnites captured Plistica. They also gained control of Sora, on the River Liris, probably with the help of a pro-Samnite faction in the city, and at the same time increased the size of their army.
The Roman army was probably some distance to the south-east of Sora, around Saticula. During the siege it was probably commanded by the consuls L. Papirius Cursor and Q. Publilius Philo, but faced with this new crisis the Romans appointed Quintus Fabius as dictator, with Quintus Aulius as his master of horse. The dictator then led his army towards Sora.
Livy records two versions of the battle. In both cases the Romans were besieging Sora, when their scouts reported that a large Samnite army was drawing near. The Roman commander, here records as the consul, marched to intercept the Samnite army, meeting up with them at Lautulae, close to the port of Tarracina. In the first account the battle lasted all day, and ended as a draw. In the second the Romans suffered a defeat in which Quintus Aulius, the master of horse, was killed. In this version of events a new master of horse, C. Fabius, was sent with reinforcements, and the combined army won a fresh victory, before resuming the siege of Sora.
Diodorus Siculus records the battle as a significant Roman defeat. After capturing Plistica the Samnites had been reinforced, and it was the presence of this large hostile army close to Latium that convinced the Romans to appoint Quintus Fabius as dictator, with Quintus Aulius as his master of horse. The Romans suffered heavy losses, and the army began to panic. Only Quintus Aulius refused to flee, and stood alone against the Samnites, dying a glorious death.
The battle of Lautulae encouraged a number of Rome's allies to change sides, but the Samnites were unable to take advantage of their victory. In the following year the Romans won a clear victory, probably at Tarracina, and the Samnites were expelled from Latium. Although the war dragged on for another decade, the Romans were rarely seriously threatened again.