For the first 700 years, until 50BC, Rome was a Republic. From 50BC till the official fall of Rome in 410 they were ruled by Ceasars. Their greatest prosperity was from100 BC till around 200 AD when Rome became a Christian nation. During that period, their wealth can from robbing and pillaging other peoples. Other than art, Rome produced nothing but an effective army. In fact, at the time of Jesus, there were more slaves in Rome than citizens. From around 200 AD until the official fall, when the Visagoths walked into the city and sacked it, they were ruled by Christians
Pres. Reagan declared Amnesty for 11 million illegals back in the 80's. All that did was encourage another flood of illegals.