2018, Ben Vinson came to a similar conclusion. Often called the or the , there was, in fact, no fixed system of classification for individuals, as careful archival research has shown. There was considerable fluidity in society, with the same individuals being identified by different categories simultaneously or over time. Individuals self-identified by particular terms, often to shift their status from one category to another to their advantage. For example, both and Spaniards were exempt from tribute obligations, but were both equally subject to the Inquisition. , on the other hand, paid tribute yet were exempt from the Inquisition. In certain cases, a might try to "pass" as an to escape the Inquisition. An might try to pass as a to escape tribute obligations. Casta paintings produced largely in 18th-century Mexico have influenced modern understandings of race in Spanish America, a concept which began infiltrating Bourbon Spain from France and Northern Europe during this time. They purport to show a fixed "system" of racial hierarchy which has been disputed by modern academia. These paintings should be evaluated as the production by elites in New Spain for an elite viewership in both Spanish territories and abroad portrayals of mixtures of Spaniards with other ethnicities, some of which have been interpreted as being pejorative in nature or seeking social outrage. They are thus useful for understanding elites and their attitudes toward non-elites, and quite valuable as illustrations of aspects of material culture in the late colonial era. The process of mixing ancestries by the union of people of different races is known in the modern era as ( , ). In Spanish colonial law, mixed-race castas were classified as part of the and not the , which set Amerindians outside the Hispanic sphere with different duties and rights to those of Spaniards and Mestizos. "Purity of blood" and the evolution of racial classification Certain authors have sought to link the castas in Latin America to the older Spanish concept of "purity of blood", limpieza de sangre, originating under Moorish rule, developed in Christian Spain to denote those without recent Jewish or Muslim heritage or, more widely, heritage from individuals convicted by the Spanish inquisition for heresy. It was directly linked to religion and notions of legitimacy, lineage and honor following Spain's reconquest of Moorish territory and the degree to which it can be considered a precursor to the modern concept of race