The near extermination of the aboriginal inhabitants of Tasmania, and the South African colonists' doctrine of apartheid are extreme examples of these attitudes at work. In contrast to this, the Chinese restricted their empire mainly to groups who could be assimilated into the Chinese way of life, though viewing groups outside the empire as racially and culturally inferior. The Romans extended Roman citizenship to a number of other urban centres and made no systematic discrimination between Italian Greek or African subjects of the empire.