A casta (Spanish: [ˈkasta], Portuguese: [ˈkastɐ, ˈkaʃtɐ]) was a hierarchical system of race classification created by Spanish elites (españoles) in Hispanic America during the eighteenth century. The sistema de castas or the sociedad de castas was used in 17th and 18th centuries in Spanish America and Spanish Philippines to describe as a whole and socially rank the mixed-race people who were born during the post-Conquest period. The process of mixing ancestries in the union of people of different races was known as mestizaje. A parallel system of categorization based on the degree of acculturation to Hispanic culture, which distinguished between gente de razón (Hispanics, literally, "people of reason") and gente sin razón (non-acculturated natives), concurrently existed and supported the idea of the racial classification system.
Created by Hispanic elites, the sistema de castas or the sociedad de castas, was based on the principle that people varied largely due to their birth, color, race and origin of ethnic types. The system of castas was more than socio-racial classification. It had an effect on every aspect of life, including economics and taxation. Both the Spanish colonial state and the Church required more tax and tribute payments from those of lower socio-racial categories. Related to Spanish ideas about purity of blood (which historically also related to its reconquest of Spain from the Moors), the colonists established a caste system in Latin America by which a person's socio-economic status generally correlated with race or racial mix in the known family background, or simply on phenotype (physical appearance) if the family background was unknown. From the colonial period, when the Spanish imposed control, many wealthy persons and high government officials were of peninsular (Iberian) and/or European background, while African or indigenous ancestry, or dark skin, generally was correlated with inferiority and poverty. The "whiter" the heritage a person could claim, the higher in status they could claim; conversely, darker features meant less opportunity.