 Complete the following phrase:  According to the CavalliSforza reconstruction of genetic history, there was little migration in Europe after the Iron Age. Most population growth can therefore be ascribed to the gradual expansion of local populations under conditions of improving fertility, rather than inter-regional transfer. That said, local migration from village to village may have been substantial; for the successful dedication and expansion of new settlements, it would have been necessary. The geography of the Mediterranean made this fairly convenient; at the beginning of the empire, about 750,000 Italians lived in the provinces. Julius Caesar, Mark Anthony and OctavianAugustus settled many of their veterans in colonies, in Italy, and the provinces. Those established in Italy up to 14 BCE have been studied by Keppie 1983. In his account of the achievements of his long reign Res Gestae, Augustus stated that he had settled 120,000 soldiers in twenty colonies in Italy in 31 BCE, then 100,000 men in colonies in Spain and southern Gaul in 14 BCE, followed by another 96,000 in 2 BCE. Brian Campbell also states From 49 to 32 BCE about 420,000 Italians were recruited  which would thus be the Veteran citizen stock that was largely sent to the provinces colonies during Augustus; The Lex Calpurnia however also allowed citizenship to be granted for distinguished bravery  as example the 1,000 Socii from Camerinum after 