Most slaves were prisoners of war that the Romans captured while expanding their empire. They were brought back to Rome to do the worst jobs in return for their keep. 

Slaves brought a good price. Most slaves worked in homes or in fields. The jobs they did depended on who owned them. In the home, slaves cooked meals, cleaned, sewed, and did gardening. Some slaves were trained for jobs like being a hairdresser. The Romans brought back many educated Greeks to be slaves. They were usually tutors for the children. Educated slaves also kept the accounts. The government used slaves to build roads, bridges, and aqueducts.

Many slaves were taken to the mines. Mining was hard work. Many slaves died working in the mines. 

Occasionally a slave and a master would become good friends. The master could give the slave money for his work. Slaves could even buy their freedom with this money.