The most famous example of a caste system is the Hindu caste system of ancient India, with Nepal, Pakistan and Sri Lanka having similarly structured systems. Nepalese castes are directly derived from the Hindu castes found in India, but the Pakistani social structure is not widely recognized as castes, despite carrying similarities. The Sri Lankan caste system was inspired by the Varnas and Jaati systems of India but carried its own strata and ended with the end of the monarchy.
Caste systems have existed throughout Africa, Europe and Asia for thousands of years. Korea, Indonesia, China, Japan and Mongolia all had caste systems of their own at different levels of stratification.
Indian castes are the most famous in the modern age because they are the most evident to the world, even in current social and political climates. Although a reformation of the caste system occurred during the Indian grab for independence, the caste system was then cannibalized by the current democracy and can be seen in the legal and social difficulties that people of certain castes still experience.
Many other caste systems have since been abolished but can still be seen in North Korea and all throughout Africa. African caste systems, like most, were separated by the role individuals played in their society. A bard fell within their own caste in the Mali empire, for instance, and that bard's children would then be in the same caste.