Farming and plunder were the most popular ways of providing for one's family during the early period of Roman history. Not just for Rome, but her neighbors, as well. Rome formed treaties with neighboring villages and city-states to allow them to join forces either defensively or aggressively. As was true throughout most of ancient history, there was usually a respite from fighting over the winter. In time, the alliances began to favor Rome. Soon Rome became the dominant city-state in Italy.
Then the Roman Republic turned its attention to its area rival, the Carthaginians, who had an interest in nearby territory.
At the beginning of the 5th century B.C., shortly after the expulsion of the Roman kings
, the Romans won a battle at Lake Regillus that Livy describes in Book II of his history. The battle, which, like most events of the period, contains legendary elements, was part of a war between Rome and a coalition of Latin states, often called the Latin League
The cities of Veii and Rome (in what is modern Italy) were centralized city-states by the fifth century B.C. For political as well as economic reasons, both wanted control of the routes along the valley of the Tiber. The Romans wanted Veii-controlled Fidenae, which was on the left bank, and the Fidenae wanted the Roman-controlled right bank. As a result, they went to war against each other three times during the fifth century B.C.
The Romans were badly defeated at the Battle of the Allia, although we don't know how many escaped by swimming across the Tiber and fleeing to Veii. The defeat at Allia ranked with Cannae as the worst disasters in Roman Republican military history.
The Samnite Wars helped establish Rome as the supreme power in Italy. There were three of them between 343 to 290 and an intervening Latin War.
Sparta's one colony, Tarentum, was a wealthy commercial center with a navy, but an inadequate army. When a Roman squadron of ships arrived at the coast of Tarentum, in violation of a treaty of 302 that denied Rome access to its harbor, they sank the ships and killed the admiral and added insult to injury by spurning Roman ambassadors. To retaliate, the Romans marched on Tarentum, which had hired soldiers from King Pyrrhus of Epirus. The Pyrrhic War spanned c. 280-272.
The Punic Wars between Rome and Carthage spanned the years from 264 - 146 B.C. With both sides well-matched, the first two wars dragged on and on; eventual victory going not to the winner of a decisive battle, but to the side with the greatest stamina. The Third Punic War was something else entirely.
Rome fought 4 Macedonian Wars between 215 and 148 B.C. The first was a diversion during the Punic Wars, in the second Rome officially freed Greece from Philip and Macedonia, the third Macedonian War was against Philip's son Perseus, and the fourth Macedonian War made Macedonia and Epirus a Roman province.
The Historical Atlas by William R. Shepherd, 1911.
153 - 133 B.C. -- no longer the early
During the Second Punic War (218 to 201 B.C.), the Carthaginians tried to make stations in Hispania from which they could launch attacks on Rome. An effect of fighting against the Carthaginians, was that the Romans gained territory on the Iberian peninsula. They named Hispania one of their provinces after defeating Carthage. The area they gained was along the coast. They needed more land inland to protect their bases.
Public Domain. Courtesy of Wikipedia.
The Jugurthine War (112-105 B.C.) gave Rome power, but no territory in Africa. It was more significant for bringing into prominence two new leaders of Republican Rome, Marius, who had fought alongside Jugurtha in Spain, and Marius' enemy Sulla.
The Social War (91-88 B.C.) was a civil war between the Romans and their Italian allies. Like the American Civil War, it was very costly. Eventually, all Italians who stopped fighting or just those who had remained loyal gained the Roman citizenship they'd gone to war for.