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n o t e s IntroductIon I thank David Freidenreich for his generous editing and suggestions, as well as Jonathan Decter for his comments on an earlier draft of this essay. I also thank an anonymous reader of this volume for useful comments. 1. For a detailed discussion of a variety of approaches and terminologies used in the discussion of “border crossings” in the context of Islam, see James E. Montgomery, “Islamic Crosspollinations,” in Islamic Crosspollinations: Interactions in the Medieval Middle East, ed. Anna Akasoy, James E. Montgomery, and Peter E. Pormann (Cambridge: Gibb Memorial Trust, 2007), 148–93. 2. Daniel Boyarin, Border Lines: The Partition of Judaeo-Christianity (Philadelphia: University of Pennsylvania Press, 2004), 1–2. 3. Nevertheless, rife during the Islamic period was the accusation of duplicity in religion —secretly holding Manichaean, Zoroastrian, or, in a later period, Ismaʿili or Jewish beliefs while outwardly professing Islam. On such accusations put forth by Muslims, see Bernard Lewis, “The Significance of Heresy in Islam,” in Islam in History: Ideas, People, and Events in the Middle East (Chicago: Open Court, 2001), 275–94, esp. 285–87. From the other side of the question, on the sincerity of Jews living in the medieval Islamic world who converted to other religions, see Sarah Stroumsa, “On Jewish Intellectuals Who Converted to Islam in the Early Middle Ages,” in The Jews of Medieval Islam: Community , Society, Identity, ed. Daniel Frank (Leiden: Brill, 1995), 179–97. Crypto-Judaism also existed under the Almohads in Morocco: see S. D. Goitein, A Mediterranean Society, 5 vols. (Berkeley: University of California Press, 1967–93), 2:300, 591n3. Regarding the lines between Judaism and Christianity, it is important to note that Shlomo Pines believed that certain groups of Judeo-Christians continued to exist well into the Islamic period. See the articles collected in Shlomo Pines, Studies in the History of Religion, ed. Guy G. Stroumsa (Jerusalem: Magnes Press, 1996), 4:211–380. 4. Marshall G. S. Hodgson, The Venture of Islam: Conscience and History in a World Civilization, 3 vols. (Chicago: University of Chicago Press, 1974). 5. See, e.g., Richard Bulliet, “Review of Venture of Islam,” Journal of the American Oriental Society 98.2 (1978): 157–58; Edmund Burke, “Islamic History as World History: Marshall Hodgson, The Venture of Islam,” International Journal of Middle East Studies 10.2 (1979): 241–64; and John Wansbrough, “Review of The Venture of Islam,” Bulletin of the School of Oriental and African Studies 40.1 (1977): 169–70. 6. See Ira M. Lapidus, A History of Islamic Societies, 2nd ed. (Cambridge: Cambridge University Press, 2005), 3–9. Lapidus explicitly acknowledges Hodgson. Lewis raises similar issues in his discussion of the word “Islam,” without reference to Hodgson. Bernard Lewis, Jews of Islam (Princeton, N.J.: Princeton University Press, 1984), 4–6. 7. On Goitein’s view of the Mediterranean as a unifying and unified entity, culturally, socially, and economically, see Joel Kraemer, “Goitein and His Mediterranean Society” [Hebrew ], Zemanim 34–35 (1990): 6–17. 8. For discussion of Goitein as historiographer and his evolving view of the relationship between Islam and Judaism, see Gideon Libson, “Hidden Worlds and Open Shutters : S. D. Goitein Between Judaism and Islam,” in The Jewish Past Revisited: Reflections on Modern Jewish Historians, ed. David N. Myers and David B. Ruderman (New Haven, Conn.: Yale University Press, 1998), 163–98. 9. See, e.g., Américo Castro, La realidad histórica de España, 3rd ed. (Mexico: Editorial Porrúa, 1966), 429–35; Castro, España en su historia: Cristianos, moros y judios (Buenos Aires: Editorial Losada, 1948), 206–14. Castro uses the terms “tolerancia” and “convivencia” in his discussions of the interactions between religions during the Muslim period in Iberia. 10. See Steven M. Wasserstrom, Between Muslim and Jew: The Problem of Symbiosis Under Early Islam (Princeton, N.J.: Princeton University Press, 1995), 3–7. 11. A. I. Sabra, “The Appropriation and Subsequent Naturalization of Greek Science in Medieval Islam,” History of Science 25 (1987): 223–43; Dimitri Gutas, Greek Thought, Arabic Culture: The Graeco-Arabic Translation Movement in Baghdad and Early ʿAbbâsid Society (New York: Routledge, 1998). 12. See, e.g., Claire Sponsler, “In Transit: Theorizing Cultural Appropriation in Medieval Europe,” Journal of Medieval and Early Modern Studies 32.1 (2002): 17–39. 13. See the discussion in Jonathan P. Decter’s chapter in this volume. 14. Ivan Marcus, Rituals of Childhood: Jewish Culture and Acculturation in Medieval Europe (New Haven, Conn.: Yale University Press, 1996...

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