In the case of the Alhambra Decree of 1492, the primary purpose was to eliminate Jewish influence on Spain's large converso population, and ensure they did not revert to Judaism. Over half of Spain's Jews had converted in the 14th century as a result of the religious persecution and pogroms which occurred in 1391. They and their Catholic descendants were not subject to the Decree or to expulsion, yet were surveilled by the Spanish Inquisition. British scholar Henry Kamen has said that