The Italian peninsula was inhabited by different tribes that were destroyed or assimilated during the Roman conquest of Italy. All these different groups were united under Roman rule for centuries and became what we now call "Italians". Today's Italians are descendants of all those groups of people. During the last years of the Wester Roman Empire and after the fall of Rome, other ethnic groups arrived in Italy, but not in sufficient numbers to cause an important demographic change. Genetically speaking, Italians are descendants of the people that inhabited the Italian peninsula during Roman times. The closer to Rome, the closer is the genetic affinity.