Slavery formed an integral part of the Roman way of life. Slaves had been a large part of the workforce that had served the wealthy in Italy and Sicily ever since the period of overseas expansion had begun at the end of the third century BCE. According to the best modern estimates, there were about two (but some estimates go as high as three) million slaves in Italy by the end of the first century BCE. Thus, slaves made up 35 to 40 percent of the total estimated population