Yosef Hayim Yerushalmi, the famous author of Zakhor: Jewish History and Jewish Memory and From Spanish Court to Italian Ghetto: Isaac Cardoso : A Study in Seventeenth-Century Marranism and Jewish Apologetics raised the following question with respect to the history of Iberian Jews :
“Will we ever know how many Jews were lost over the years? Amongst the Jews who were lost must be counted not only those who were the victims of massacres and martyrdoms, but equally those who went over to the other side or converted. And these Jews were lost not because- as the most simplistic explanation would have it- they were seduced by purely secular ambitions or material benefits; they were conquered by a real, a genuine despair; they feared that the Jewish people had no future.”
 Yerushalmi quoted in Brbau, Pierre, “Exile, Assimilation, and Identity: from Moses to Joseph,” in Carlebach, et al. 250. Shelomo Alfassa, The Sephardic ‘Anousim’: Anousim, Crypto-Jews, and Marranos, (New York, Alfassa: 2010), pp. 48-49.