What medieval institution was created to fight heresy in parts of Europe?

The Inquisition, created by the papacy in the 13th century, was a network of church courts empowered to investigate and suppress heresy, especially movements like the Cathars and Waldensians. Using the inquisitorial procedure (judges actively gather evidence rather than relying on accusers), it interrogated suspects, imposed penances, and, in obstinate cases, handed the condemned to secular authorities for punishment. Papal bulls like Ad extirpanda (1252) authorized limited use of torture. Dominican and Franciscan friars often served as its examiners, reflecting the era’s drive for doctrinal uniformity. Over time, different branches emerged—most famously in Spain and later Rome—each with distinct aims and methods. Beyond trials, it also policed preaching and books, showing how medieval and early modern authorities fused religion, law, and governance to enforce orthodoxy.