yes
In the civil war slaves were still slaves but still, they were with the enemy and were as such treated as the enemy.
Prisoners of war were enslaved. They were the sources of slaves in antiquity.
no
Afonso I of Kongo sold enemies and prisoners of war as slaves to the Portuguese during the transatlantic slave trade in the 16th century.
False!
As war prisoners or purchase of them from other peoples.
Sacrifices usually were slaves or prisoners of war
The Ancient Egyptians conquered other countries nearby, and made slaves of war prisoners
Most slaves were prisoners of war.
The tribes or cities which captured them could kill them, enslave them, sell them as slaves, or trade them with the Romans for their own prisoners, or some other deal.
There were few slaves in Egypt before the expansionist policies of the New Kingdom pharaohs brought thousands of prisoners of war into the kingdom.
It was the custom during that period that Prisoners of War became Slaves. This applied to enemy soldiers, women and children captured.