The Papal Inquisition began in 1232, under the auspices of Pope Gregory IX, as a reaction to the heresies that threatened to break up the unity of the Church. The purpose of the Inquisition was to ferret out heretics and force them to accept Catholicism as practiced and taught by the Church.
Public inquiries were set up town by town. People were encouraged to report heretics, and because their identity was kept secret, many came forward with names. Heretics who confessed received a penance (a kind of religious fine), which could be anything from reciting prayers to a flogging. Those who refused to accept the charges against them and “repent” were punished. Some were burned at the stake or hanged.
The Papal Inquisition lasted through most of the thirteenth century. It was conducted mostly in the south of France, northern Italy, and northern Spain. It reappeared in fifteenth-century Spain in its most virulent form. The Spanish Inquisition still horrifies us, even to this day.The Spanish Inquisition
In Spain, the inquisition was initiated by the monarchy — that is, it was a political as well as a religious institution. King Ferdinand and Queen Isabella (the monarchs who funded Columbus's voyages) needed a cause under which they could unify the Spanish people into a powerful nation. They also needed money.
They chose the unifying force of Catholicism and asked the pope for permission to begin the Inquisition, whose purpose was to “purify” the land. Muslim and Jewish converts to Catholicism, Protestants, nonbelievers, and Christians who did not see eye-to-eye with any aspect of the Catholic dogma all needed purifying. Conveniently, the state appropriated all possessions that belonged to the executed heretics.