in Colonial Spanish America. The idea in New Spain that native or "Indian" (indio) blood in a lineage was an impurity may well have come about as the optimism of the early Franciscans faded about creating Indian priests trained at the Colegio de Santa Cruz de Tlatelolco, which ceased that function in the mid-sixteenth century. In addition, the Indian nobility, which was recognized by the Spanish colonists, had declined in importance, and there were fewer formal marriages between Spaniards and indigenous women than during the early decades of the colonial era. In the seventeenth century in New Spain, the ideas of purity of blood became associated with "Spanishness and whiteness, but it came to work together with socio-economic categories", such that a lineage with someone engaged in work with their hands was tainted by that connection. Indians in Central Mexico were affected by ideas of purity of blood from the other side. Crown decrees on purity of blood were affirmed by indigenous communities, which barred Indians from holding office who had any non-Indians (Spaniards and/or Black peoples) in their lineage. In indigenous communities "local caciques [rulers] and principales were granted a set of privileges and rights on the basis of their pre-Hispanic noble bloodlines and acceptance of the Catholic faith." Indigenous nobles submitted proofs (probanzas) of their purity of blood to affirm their rights and privileges that were extended to themselves and their communities. This supported the república de indios, a legal division of society that separated indigenous from non-Indians (república de españoles). Casta classifications and legal consequences In Spanish America racial categories were registered at local parishes upon baptism as required by the Spanish Crown. Initially in Spanish America there were three ethnic categories. They generally referred to the multiplicity of indigenous American peoples as "Indians" (indios). Those from Spain called themselves españoles. The third group were black Africans, called negros (lit. "blacks"), brought as slaves from the earliest days of Spanish Empire. Although intermarriage was widespread from the beginning of the colonial period, mestizos only slowly began to be recognized as a distinct ethnicity 150 years after the Spanish conquest of the Aztec Empire, prior to which they had simply been identified as Spaniards. Although the number of Spanish women emigrating to New Spain was far higher than is often portrayed, they were fewer in number than men, as well as fewer black women than men, so the