By 1492, tribunals of the Spanish Inquisition existed in eight Castilian cities.
Those cities were Ávila, Córdoba, Jaén, Medina del Campo, Segovia, Sigüenza, Toledo, and Valladolid. The network grew rapidly after Pope Sixtus IV authorized a new, monarchy-controlled Inquisition for Castile in 1478. The first inquisitors were appointed in 1480, and Seville became the site of the institution’s first major operations.
The figure eight refers specifically to Castilian cities with tribunals by that date, not to every tribunal under the Spanish Crown. Aragon had a separate group of tribunals, while later expansion reached places such as Sicily, Sardinia, Lima, Mexico City, and Cartagena. This distinction causes common confusion with the much larger imperial network that developed over subsequent centuries.
The tribunals initially concentrated on converts from Judaism who were suspected of secretly observing Jewish practices. After the 1492 expulsion of Jews who refused conversion, the Inquisition continued investigating conversos and later pursued alleged Moriscos, Protestants, blasphemers, bigamists, and others accused of religious offenses.