In 1981, Ratzinger was named Prefect of the Congregation for the Doctrine of the Faith, the organization which until 1965 had been called the Holy Office of the Inquisition, making him Grand Inquisitor.
Remember the Inquisition when those zany Catholic zealots used torture and murder to acquire the property of dissenters? They employed the use of thumbscrews and the rack against women (witches), Jews, Muslims and others who failed to recognize the "One True Church." They didn't just kill people, they also tortured and killed kitties (the preferred animal companion of witches and other non-Catholics), rats infected with the plaque proliferated and many more Europeans died.
The office of Inquisition was never eliminated, they just changed it's name.
The Inquisition was set up in the City of Rome by the cruel Pope Paul IV when he was still Cardinal Carafa, because he was peeved at the success of the Spanish Inquisition. He realised it was time to give some teeth to the Italian tribunal. He persuaded his predecessor, Paul III, to institute the Roman Inquisition with the papal bull of 1542 Licet ab init.
The tribunal constituted by that bull was the Sacra Congregation Romanae et Universalis Inquisitionis seu Sancti Officii – the Sacred Congregation of the Roman and Universal Inquisition or Holy Office. Later, as pope, he oversaw it with a rod of iron.
In 1965, amidst the liberal atmosphere of Vatican II, Pope Paul VI changed its name again, to Congregatio pro Doctrina Fidei or Congregation for the Doctrine of the Faith – a title better suited to an enlightened age. Meanwhile he jettisoned only such powers as the times made it impossible to retain. So readers might be tempted to think that although the building still stands, its activities must have changed. Surely Rome cannot get away with that kind of thing these days?