The Samnite Wars were fought in 343-341 BC, 326-304 BC, and 298-290 BC as the Roman Republic of Latium expanded south towards the lands of the powerful Samnites. The Samnites were one of early Rome's most formidable rivals, and the three wars fought between Rome and Samnium resulted in the Roman conquest of Lazio, Abruzzo, Molise, Campania, Basilicata, and northern Apulia after fifty years of costly battles at Mons Gaurus, Caudine Forks, and Sentinum.
Background[]
By the mid-4th century BC, Italy was still divided between Latins, Greeks, Etruscans, and other civilizations, with the Oscan-speaking, semi-nomadic Samnites being one of the most powerful nations on the peninsula. The Samnites, who lived along the Apennine mountain range, were a tribal confederation consisting of the Hirpani, Caudini, Pentri, and Carricini, and the four, often-divided tribes made up the Samnite League. The League was normally governed by a central council made up of all four tribes led by a warchief, and, in 354 BC, the Roman Republic and the Samnites allied against a common enemy, the Volsci. However, relations quickly soured, as, just over a decade later, the Samnites attacked the Sidicini and Campanians who came to aid them.
Wars[]
First Samnite War and Latin War[]

Italy at the start of the wars
Despite their alliance with the Samnites, Rome was unwilling to risk a rival power gaining hegemony over Campania's agriculturally-rich land, and Rome intervened on behalf of the coastal confederation, whose members submitted themselves to the Republic. In 343 BC, the Romans defeated the Samnites at Mons Gaurus, Saticula, and Suessula; before the Romans could take advantage, however, Rome's Latin allies rose in rebellion in the "Latin War", forcing the Romans and Samnites to make peace and resume their alliance. The Campanians and Sidicini were motivated to join the anti-Roman uprising, and, in 340 BC, the Romans crushed the uprising at Mount Vesuvius; it was not until 337 BC that the Latins were forced to submit to Roman authority. A hierarchy was created in which Rome's Latin subordinates no longer had military or diplomatic dealings with other powers, and the inhabitants of loyal cities such as Aricia and Lanuvium became Roman citizens, while the disloyal but crucial port city of Antium received the same perk, along with a Roman garrison.
Second Samnite War[]

Map of the second war
However, hostilities between the Romans and the Samnite League resurfaced in 328 BC when a Roman colony was established at Fregellae on the Samnite side of the River Liris, and this, coupled with the expanding Roman presence in Campania, led to further deterioration of relations. In 326 BC, a pro-Roman faction in Neapolis expelled the Samnite garrison and handed over the city to Roman control. The war began with a Roman offensive into western Samnium, and Quintus Fabius Maximus Rullianus disobeyed orders by attacking a Samnite army and winning a great victory at Imbrinium. Roman pressure continued to build in the years after, and, in 321 BC, the Samnite council appointed the statesman Gaius Pontius as commander for the year. He decried any thought of surrender and proclaimed the just nature of the war on Rome. He and his army encamped at Caudium, where they awaited the arrival of a Roman consular army. In the ensuing Battle of Caudine Forks, the Samnites surrounded the Romans in a mountain pass and rained missiles on them until they agreed to surrender, and Pontius - ignoring his father's advice to massacre them - let them surrender and be paroled, taking 600 equites as hostages for good measure. A five-year-long break in hostilities followed this humiliation, and Rome's inflexible Greek phalanx was replaced by the manipular legion; Rome used these years to rearm, train, and drill in the new style.

Roman troops invading Samnium
In 315 BC, Rome renewed the conflict, quickly capturing Saticula. The Romans were defeated at Lautulae, allowing for the Samnites to sack Roman lands. However, in 314 BC, the Romans crushed a Samnite army at Terracina, proving to be the tipping point. Luceria and the lands around it fell to the Romans shortly after, and Fregellae was recovered in 313 BC. In 312 BC, the Romans founded new colonies and built the Appian Way to facilitate military logistics. In 310 BC, the Etruscans briefly joined the war on the Samnite side, but they were defeated at Lake Vadimo, curtailing their war-making capacity. Rome then used its allies and road network to overpower Samnium, forcing the Samnites to make peace in 304 BC. The Romans tripled their territory during the war, and, from 302 to 298 BC, the Romans fought annual campaigns in Umbria and Etruria simultaneously to expand their borders. By this point, Roman empire-building in the Italian peninsula alarmed many of the independent peoples.
Third Samnite War[]

Southern Italy in 290 BC
In 297 BC, the Samnites their southern frontier and invaded Lucania, laying waste to it and forcing the Lucanians to send panicked emissaries to Rome. The Roman Senate, seeking an opportunity to fight a just war and crush Samnite power, allied with the Lucanians and then demanded that the Samnites withdraw. When the Samnites withdrew, the Third Samnite War began. The legions undertook destructive campaigns in both Samnite and Etruscan territory, and, rather than be defeated piecemeal, the Samnite leader Gellius Egnatius marched into Etruria and joined forces with the Etruscan armies there. The united army was defeated in 297 BC, but Rome had more trouble with a united front. Egnatius formed a grand alliance of Samnites, Etruscans, Umbrians, and mercenary Senones against Roman expansion, and a Roman double-consular army invaded Umbria in 295 BC. This army faced the allied Samnite army at the Battle of Sentinum, during which the Romans won a hard-fought and costly victory; they lost 8,700 men and their heroic consul, Publius Decius Mus, but the Samnites had lost 25,000 men, plus 8,000 prisoners. Meanwhile, 3,000 more Etruscans were slain in Etruria, and, while the Samnites and Gauls continued to resist Rome for another half-decade, Sentinum decided the fate of Italy. In 290 BC, the Third Samnite War ended, and the vast majority of central Italy fell under Roman control.