Between the 12th and 16th centuries, the forced Christianization of the Iberian Peninsula provides a clear example of how Christianity curtailed the practice of other faiths during the Middle Ages and Humanism. During the Reconquista, the Christian kingdoms imposed Christianity as the dominant religion, subordinating Muslims and Jews to conversion or expulsion. The establishment of the Spanish Inquisition at the end of the 15th century further strengthened religious control, monitoring orthodoxy and punishing deviations through trials, persecutions, and confiscation. Muslim and Jewish places of worship were destroyed or converted to churches, consolidating religious and social hierarchies based on confessional affiliation. Even while considering the mutual manifestations of intolerance between Christians and Muslims, in the legal sphere there were interesting episodes of cross-fertilization between the two cultures; studying the Reconquista and forced process of Christianization helps to understand how religious norms and power strategies contributed to the exclusion and control of minorities, offering a historical perspective on the dynamics of religious and social exclusion between the Middle Ages and Humanism.