The Roman Empire grew on the backs of slaves. Estimates point to slaves making up 1/5 or even 1/3 of the Roman population. Slaves were often people who the Roman's conquered in war. Pirates also kidnapped and sold slaves throughout the Empire, while others were born into it. Slaves did all manner of work in Rome, from agriculture and construction, to teaching and entertainment. Under Roman law, enslaved people had no personal rights and were regarded as the property of their masters. They could be bought, sold, and mistreated at will and were unable to own property, enter into a contract, or legally marry.