In 1492, when King Ferdinand II of Aragon and Queen Isabella I of Castile gave Jews who had not yet converted the choice to either convert to Catholicism or leave Spain, in some towns the entire community left, in others the entire community converted. There were large numbers of Conversos in Castile, Aragon, Andalusia and Valencia. Within a century, the majority had melted into the Christian population, but. . .continued to be suspected of being secret Jews (Marranos). If denounced, they were interrogated and could be burnt at the stake. . .or imprisoned. . .their property confiscated and their families. . . stigmatized for generations. Inquisitors visited homes on Fridays to see if families put white tablecloths and candlesticks on the table to celebrate the Sabbath. The dreaded Inquisitor General Tomas de Torquemada – himself a Converso – would stand on a hill above a city on Saturdays to identify the houses where there was no smoke coming out  of the chimneys (Jewish laws prohibit any work, including cooking and lighting a fire, on the Sabbath). Records of the Inquisition show that food was used as evidence of Judaizing when women were brought to trial. Because of the many religious rules related to food, cooking was central to the Jewish identity. So as not to use pork fat as Christians did for cooking, and to avoid clarified butter, which the Muslims used (their dietary laws forbid mixing meat with dairy products), Jews used olive oil exclusively for all their cooking. The smell of frying with olive oil became so strongly associated with Jewishness that even Old Christians of non-Jewish descent avoided it for fear of being mistaken for secret Jews. From The Food of Spain: A Celebration by Claudia Roden