Inquisitors were officials in the Catholic Church responsible for investigating and prosecuting heresy, which is the belief in ideas contrary to church doctrine. They played a key role during the Inquisition, a series of campaigns aimed at maintaining religious orthodoxy. Inquisitors had the authority to interrogate suspects, gather evidence, and impose penalties, including imprisonment or execution. The most famous inquisitions occurred in the late medieval and early modern periods, particularly in Spain and Portugal. Inquisitors often worked in secret, leading to widespread fear and suspicion. Their actions significantly influenced religious and social dynamics in Europe, shaping the relationship between the church and its followers.