Isabella sought inquisitors to investigate Christians suspected of keeping the faith of their Jewish ancestors. Baptism had brought their families into the Church. It would also give the new tribunal its claim over them.
On 1 November 1478, Pope Sixtus IV issued a bull at Rome authorising Isabella and her husband, Ferdinand, to appoint inquisitors in Castile. The document supplied the authority from which the Spanish Inquisition would develop. The monarchs had asked for it. Their petition alleged that people who had received Christian baptism were secretly returning to Jewish religious observance and passing those beliefs to their children.
Isabella was twenty-seven. She had been proclaimed Queen of Castile in December 1474, but possession of the crown had brought a war over her right to wear it. Supporters of her niece, Joanna, backed by Portugal, contested the succession. That struggle would continue until 1479. In November 1478, the queen seeking authority over her subjects' religious lives was still securing her own royal position.
Four months earlier, on 30 June, Isabella had given birth to her son Juan in Seville's Alcázar. The city celebrated with music and public festivities. The royal family now had a male heir, born in a year when the crown he stood to inherit was still being fought over.
Ferdinand shared in the government of Castile, and the request to Rome belonged to them both. Isabella was the reigning queen, devout and with powers of her own. The bull addressed her alongside her husband and granted them a practical role in the prosecution of heresy. Her place in this story is among the people who requested that power and received it.
The people most immediately exposed were conversos, converts from Judaism and their descendants. The word covered families whose religious lives could be very different. Some continued Jewish observances in secret; others were practising Christians. Jewish ancestry did not tell an inquisitor what a person believed. An accusation could nevertheless make the question a matter for a court.
Baptism made the distinction legally important. The tribunal's business was heresy among Christians, especially the allegation that a baptised person was observing Judaism. Jews who had remained Jewish were outside that particular jurisdiction. For a converso, belonging to the Church brought obligations which the inquisitors could enforce, including an obligation to abandon the religion of their ancestors.
The royal petition treated the matter as an urgent danger. As the bull recounted it, the alleged offenders were spreading their beliefs within families and among other people. It even connected religious wrongdoing and the failure to suppress it with wars and other calamities. A suspicion about what happened in a household had become an explanation for what was wrong in a kingdom.
That was the case the monarchs put to Rome, and the Pope granted it.
The powers granted were specific. Isabella and Ferdinand could choose the inquisitors, remove them and put others in their place. The men were to be clerics over forty years of age, with learning in theology or canon law. These were ecclesiastical judges exercising authority sanctioned by the Pope, but the Crown had gained a hand in deciding who would exercise it. Piety came with appointments to make.
The authority was not used at once. Almost two years passed before the first inquisitors, two Dominican friars, were appointed in September 1480. They reached Seville that December, and the city's Dominican convent of San Pablo became their first base. The permission obtained at Rome was acquiring men, rooms and a place where people could be summoned.
As the tribunal began its work in the early 1480s, the search for religious error reached into domestic routines. The signs that Seville's inquisitors set out in 1481, which became a model for later lists, included bringing out fresh linen for the Sabbath and preparing its food on Friday. Such observances appeared in accusations intended to identify people secretly maintaining Jewish religious life.
Linen and the preparation of a meal could become evidence.
A household was a place where religion could be passed on through repeated acts, without a written argument about belief. The tribunal's attention to those acts gave family customs a dangerous public significance. What someone had seen at home could be described before judges as a sign of heresy. The accusation still required interpretation, but the men interpreting it held their places by the authority Isabella and Ferdinand had requested.
By February 1481, six conversos had been burned in Seville after being condemned as heretics for practising Judaism. It was the city where, two and a half years earlier, music had greeted the birth of Isabella's son. The inquisitors' claim over the six rested on the Christian baptism that had brought them into the Church.
