On what date was the Spanish Inquisition definitively disbanded?

The Spanish Inquisition was definitively disbanded on 15 July 1834.

The abolition came through a royal decree issued during the regency of Maria Christina of the Two Sicilies, who governed for her young daughter, Isabella II. Francisco Martínez de la Rosa led the government at the time, and the decree formally suppressed the Tribunal of the Holy Office of the Inquisition.

This was not the Inquisition’s first interruption. The Cortes of Cádiz abolished it in 1813, but Ferdinand VII restored it in 1814. It was abolished again during the Liberal Triennium in 1820, then restored after Ferdinand’s return to absolutist rule in 1823. The 1834 decree was therefore regarded as the final and definitive suppression.

The institution had begun in 1478, when Pope Sixtus IV authorized Ferdinand II of Aragon and Isabella I of Castile to establish a royal Inquisition. Its long history included investigations of conversos, Moriscos, Protestants, alleged heretics, and other religious offenders.