The ancient Proto-Italic people traveled south into the Italian Peninsula sometime in the 1000s BCE. There, they established settled societies and gradually diverged into their various dialects. Scholars today know of these dialects thanks to classical sources penned (or carved into stone) by their speakers or by those of different dialects who identified their linguistic cousins.
However, the Italic languages did not exist in a vacuum; they were also deeply influenced by the Greek language and the Etruscan language, which were commonly spoken in regions of Italy. Many loanwords from those languages can be found in Latin, for example. The scribes of the Latin language borrowed their alphabet from the Etruscan people, who borrowed it from the Greek people, who in turn borrowed it from the ancient Phoenician people (who established the colony of Carthage, which took control of Sicily). So, the Italic languages existed in a vast network of interaction and sharing with other languages.
Rise of Rome
Ancient Italy was not a peaceful utopia of cross-cultural interaction, however. There were many wars over the ancient period, with the various tribes and city-states competing for power and influence. One such city-state, Rome, gradually rose to become the most powerful faction in Italy. In the 500s BCE, the Roman Republic conquered the other local Latin-speaking peoples. Over the subsequent centuries, Rome gradually expanded, taking control of the Samnite tribes, southern Italy, the Etruscan speakers, and, finally, the rest of Italy after defeating the Carthaginian Empire.
By 200 BCE, the Roman Republic ruled over the Italian Peninsula. For the next two centuries, the other Italic languages, as well as Etruscan, were gradually stamped out by Rome. This was carried out due to soft power since Rome was the economic and cultural capital of the region, and hard power since Rome often used brutal force to squash rebelling non-Roman people.
Proliferation of Latin
As Rome defeated the Carthaginian Empire, it also took control of Carthage's overseas territories. In the 100s BCE, Rome took control of Spain, Greece, Illyria, and North Africa. It also laid its first foundations in Gaul (as France was known then) and Asia Minor (as Turkey was known then). This expansion continued even as Rome suffered from political instability and transformed from a republic into an empire.
Not only did Rome conquer new lands, but it also spread its culture to these places. Roman settlers, administrators, and soldiers established new cities in distant lands, while local people who revolted were stamped out, as had been the case in Italy. While the educated upper class of the Roman Empire spoke Classical Latin, the lower classes spoke so-called Vulgar Latin. Greece continued to speak its Greek languages, however.
The Romance Languages
In the 400s CE, the Roman Empire crumbled and split into various principalities due to numerous factors. With no central authority to guide the language, Vulgar Latin split into different dialects, which grew farther and farther apart over the centuries until they were no longer mutually intelligible. The major Romance languages spoken today are Italian, Spanish, French, Portuguese, Catalan, Romansh, and Romanian. They are most popular in Western Europe, Southern Europe, Central America, and Southern America.
