Slavery-Slavery is a system under which people are treated as property
to be bought and sold, and are forced to work. Slaves can be held against their
will from the time of their capture, purchase or birth, and deprived of the
right to leave, to refuse to work, or to demand compensation. Slavery predates
written records and has existed in many cultures. In pre-industrial societies,
slaves and their labour were economically extremely important to those who
benefitted from them. Slaves and serfs made up around three-quarters of the
world's population at the beginning of the 19th century. Prehistoric graves
from about 8000 BC in Lower Egypt suggest that a Libyan people enslaved a San-like
tribe. Slavery is rare among hunter-gatherer populations. Mass slavery also requires economic surpluses
and a high population density to be viable. Due to these factors, the practice
of slavery would have only proliferated after the invention of agriculture
during the Neolithic Revolution about 11,000 years ago. Slavery was known in
almost every ancient civilization, and society, including Sumer, Ancient Egypt,
Ancient China, the Akkadian Empire, Assyria, Ancient India, Ancient Greece, the
Roman Empire, the Islamic Caliphate, the Hebrew kingdoms in Palestine, and the pre-Columbian
civilizations of the Americas. Such institutions included debt-slavery,
punishment for crime, the enslavement of prisoners of war, child abandonment,
and the birth of slave children to slaves.