What are the sources of slavery?

The main sources of supply of slaves in different countries of ancient times were usually the same. The most important source of supply of slaves for almost all states of that era was military conflicts, captured military personnel and part of the population were enslaved, and then sold or brought to a specified place where they later became slaves. People who broke the law, as well as debtors who did not pay the debt, also turned into slavery.
The slave market was also an important and diverse source of human resources.