Diego D’Aguilar (Moses/Moshe Lopez Pereira) was born in Spain, descendant to a family of crypto-Jews. His father had a tobacco monopoly. Diego D’Aguilar was separated from his parents and sister during the childhood and baptised. He subsequently was ordained a Catholic priest and was employed as a financial expert by the Inquisition. One day his sister was caught practising Judaism, and sentenced to be burned at the stake. Her mother went to her son Bishop Diego D’Aguilar to beg for her daughter’s life. After she called him Moshe Lopez Pereira he recalled his childhood and left the palace. He did not succeed in helping his sister, and his mother died on their way to Vienna where he had good connections with the Empress Maria Theresia.
At the age of 23 Diego d’Aguilar left for Vienna and returned to Judaism. In Austria he reorganized the monopoly of the tobacco business and headed it for sixteen years during which time he paid the state seven million florins per year. He was enobled as Baron d’Aguilar (1726),and named councilor to the throne. D’Aguilar and others raised large amounts of loans for the treasury (10 million florins, for 1732 alone) and helped the Empress Maria Theresia in rebuilding the Schoenbrunn Palace in Vienna. D’Aguilar was very influential in the court and helped in Jewish problems: together with others he was instrumental in preventing the expulsion of Jews from Moravia and Prague in 1744. He also helped the Jews of Mantua, Italy, and Belgrade, in 1752, and collected funds for Eretz Israel. D’Aguilar was founding member of the Sephardi congregations in Vienna and Timisoara (now in Romania). After the Spanish government tried to put him on trial for returning to Judaism, he left with his large family (14 children) to London in 1757, where he was active in the local Sephardi community. He died two years later.