What was so troubling about the period known as the Inquisition?

Answer: The Inquisition was a powerful office set up within the Catholic Church to root out and punish heresy throughout Europe and the Americas. Beginning in the 12th century and continuing for hundreds of years, the Inquisition is infamous for the severity of its tortures and its persecution of Jews and Muslims. Estimates of the number killed by the Spanish Inquisition, which Sixtus IV authorised in a papal bull in 1478, have ranged from 30,000 to 300,000. Some historians are convinced that millions died.