I've often heard of the strong role that the Roman republic/empire had in urbanizing western and northern Europe, and how areas outside Rome's influence such as Germany and eastern Europe did not urbanize until well into the middle ages. But in descriptions of the early Roman conquest of Italy, it sounds as if there were already many cities in Italy. How did Italy come to be so urbanized when at that time most of Europe outside Greece was not urbanized at all?
I would say that the reasons for this are two-fold. Firstly, the Greeks founded their first colonies in Southern Italy around 800 BCE. Their cultural influence in this area was extensive- so extensive, in fact, that the Romans referred to this part of Italy as Magna Graecia or "Great Greece." Colonists from the Greek cities brought their architecture with them and we see Greek monumental stone architecture still standing in places like Paestum, South of Naples, and Syracuse, in Sicily. In fact, one of the oldest Greek temples still standing is found in Agrigento, Sicily. Greek architecture thus had a huge impact on the architectural development of Latin and Italian cities. That influence is clearly visible in Italian temple architecture.
The second great influence on early urbanization in Italy came from the Etruscans to the North. The Etruscans were the first population on the Italian peninsula to construct cities. These first began as hilltop citadels, which were well-placed to guard against invasion by outside tribes. The Etruscans were highly advanced compared to the other indigenous populations in Italy: they could build sewers, redirect water to flow to agricultural areas, drain marshes, fire both fine and industrial-grade ceramics, and construct large wooden and stone structures. All of these skills were essential for the Etruscans to form Italy's first urban population centers. Where they attained these skills really depends on who you ask. They either developed them themselves with help from extensive trade contact with Carthage and the Greek cities, or they brought such methods with them when they immigrated to Italy from the Near East, where urbanization had already taken place.
But it is important to keep in mind that our historical accounts of the early Roman conquest of Italy were written long after the fact. They consistently fall prey to anachronism, and therefore likely portray Italy as far more urbanized than it actually was at the time. One of the oldest stone buildings found in Gabii, one of the nearby cities which was a part of those conquests, only dates back to about 350 BCE. Nevertheless, you can see the influence of the Etruscans, who were wizzes at carving and fitting together stone blocks without the use of concrete, which would later be invented by the Romans.
