The Islam conquest of Spain began in 711 CE and would extend over parts of the Iberian Peninsula through the end of the 15th century until King Ferdinand’s and Queen Isabella’s victory over the Kingdom of Granda. While the Reconquista increasingly carved out large sections of Spanish soil formerly under Islamic rule, the influence of Islamic culture on Jewish communities, especially in the area of religion remained strong through the 13th and 14th centuries.
As a consequence responses to a whole host of issues including persecution were understood differently by Jews in Islamic lands. Menahem Ben-Sasson notes that under Islamic rule, Jews generally underwent extensive cultural Arabization. The influence of Islamic-Arabic culture in the area of religious thought is clear.
Berthold Werner [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)%5D, via Wikimedia Commons
Major Jewish religious works were produced in Arabic and the philosophical trend present in Arabic thought bled over into Jewish thinking most pronounced in Maimonides’ philosophical works. As a consequence responses to a whole host of issues including persecution were understood differently by Jews in Islamic lands. These concepts likely remained in force even after the demise of Islamic hegemony.
In Christian Europe as we have seen, martyrdom or suicide was largely the preferred response to forced conversions. Whether this attitude toward martyrdom was as Mark Cohen asserts an elaboration of the martyr traditions recorded in the Midrash is unclear.
Jacob Katz argues that Ashkenazi views of martyrdom were also influenced by their conviction that Christianity was idolatrous, though no Sephardic source to my knowledge considered Christianity to be otherwise. Their views were further influenced by the willingness of Christians to suffer martyrdom. If Christians were willing to suffer martyrdom, so should Jews.
There were certainly examples of martyrdom and even self immolation among Iberian Jews, though the numbers percentage wise were smaller if only because of the disparities in population. In Gerona, for example we learn that “…the Jews claimed that the number of the dead was larger, but the jurados pointed out that many Jews-women and children- had been slain by the Jews themselves. The honorable city fathers were unwilling to debit their account with the lives of those holy innocents who committed suicide in order to escape forced conversion.” 
Cohen also notes that conversion to escape death likely occurred to a greater degree than alluded to in Hebrew accounts of the period, but that martyrdom remained the Ashkenazi ideal. Nevertheless, Rabbi Yehudah HeChasid’s references to both apostates and various acts of dissimulation in his Sefer Chasidim make it clear that the situation was more complicated in Ashkenazic lands than is often appreciated.  Rabbi Yehudah for examples points to an example in Rokeach 316 and in Teshuvot Maharil 118.
“When the members of his community were offered the alternative of either converting or being killed, he [the rabbi] advised them to convert and afterwards to return to Judaism…when things settled down, they all returned to Judaism. Nevertheless, since the rabbi counseled his flock to defect from the Jewish faith, his offspring all became apostates, and he is being punished [in the hereafter] as though he was the one who had caused them to sin.”
It is important to note that Jews did not maintain the same invectives against Islam that Ashkenazi Jews maintained toward Christianity. More importantly, the concept of martyrdom was not a similarly significant concept in Islam as it was in Christianity. As Cohen notes, in Islam, the martyr is a warrior who dies fighting in a holy war. Suicide or execution to evade conversion is not held in the same light.
The Sunni Islamic schola, Abdul Hamid Siddiqui defines Taqiyya as “Concealing or disguising one’s beliefs, convictions, ideas, feelings, opinions, and/or strategies at a time of eminent danger, whether now or later in time, to save oneself from physical and/or mental injury.” Taqiyya is a fundamental Islamic concept based on the Quran. The Quran holds blameless Muslims who disguise their beliefs in cases of safety. Mark Cohen adds:
“Confronted by religious persecution, Muslims favored outward accommodation or dissimulation, in Arabic taqiyya while inwardly maintaining belief in Islam. Rather than having a gentile model of martyrdom to emulate and even surpass, the Jews of Islam seem to have been influenced by the Islamic response to forced conversion in their own pattern of accommodation.”
In addition, in all three great Islamic persecutions of the medieval period (i.e. the persecution under al-Hakim, the Almohads, and the persecution in Yemen) Jews and Christians who were forcibly converted were eventually allowed to revert to their original faiths. The influence of taqiyya is I believe evidenced in the writings of Maimonides and his father in response to forced conversions of Jews of Morocco and Yemen. Abdul Hamid Siddiqui refers to the words of Ibn Abbas, a Sunni commentator:
“al-Taqiyya is with the tongue only; he who has been coerced into saying that which angers Allah (SWT), and his heart is comfortable (i.e., his true faith has not been shaken.), then (saying that which he has been coerced to say) will not harm him (at all); (because) al-Taqiyya is with the tongue only, (not the heart).”
Abdul Hamid Siddiqui also refers Abd al-Razak, who in his book “al- Dala-il,” wrote: “The nonbelievers arrested `Ammar Ibn Yasir and (tortured him until) he uttered foul words about the Prophet, and praised their gods (idols); and when they released him, he went straight to the Prophet. The Prophet said: ‘Is there something on your mind?’ `Ammar Ibn Yasir said: ‘Bad (news)! They would not release me until I defamed you and praised their gods!’ The Prophet said: ‘How do you find your heart to be?’ `Ammar answered: ‘Comfortable with faith.’ So the Prophet said: ‘Then if they come back for you, then do the same thing all over again.’ Allah at that moment revealed the verse: ‘….except under compulsion, his heart remaining firm in faith… [16:106]’ ”
Ibn Sa’d in his book titled al-Tabaqat al-Kubra, relates the following on the authority of Ibn Sirin:
“The Prophet (S) saw `Ammar Ibn Yasir (ra) crying, so he (S) wiped off his (ra) tears, and said: “The nonbelievers arrested you and immersed you in water until you said such and such (i.e., bad-mouthing the Prophet (S) and praising the pagan gods to escape persecution); if they come back, then say it again.”
It is clear then that for Islam, the survival of a faithful Muslim is of utmost importance. The ability to feign loyalty to another religion is not considered problematic when faced with persecution.
 Menahem Ben-Sasson, “On the Jewish Identity of Forced Converts: A Study of Forced Conversion in the Almohade Period.” Pe’amim 42 (1990): 20.
 Mark R. Cohen, Under Crescent and Cross: The Jews in the Middle Ages, (Princeton: Princeton University Press, 1994), 174.
 Yitzhak Baer, A History of the Jews in Christian Spain, Volume 2, (Philadelphia; Jewish Publication Society, 1961), p. 107.
 Ibid., 175.
 Avraham Yaakov Finkel, trans., Rabbi Yehudah HeChasid: Sefer Chasidim, (Northvale: Jason Aronson, 1997), 349-359.
 Ibid., 349.
 Qur’an 16:106
 Mark R. Cohen, Under Crescent and Cross: The Jews in the Middle Ages, (Princeton: Princeton University Press, 1994), 176.
 Ibid. Chapter 6b Siddiqui also refers to what is narrated in al-Sirah al-Halabiyyah, v3, p61, that: “After the conquest of the city of Khaybar by the Muslims, the Prophet was approached by Hajaj Ibn `Aalat and told: “O Prophet of Allah: I have in Mecca some excess wealth and some relatives, and I would like to have them back; am I excused if I bad-mouth you (to escape persecution)?’ The Prophet excused him and said: ‘Say whatever you have to say.’ In addition, alal al-Din al-Suyuti in his book, ‘al-Durr al-Manthoor Fi al-Tafsir al-Ma’athoor,’ v2, p176, narrates that: Abd Ibn Hameed, on the authority of al-Hassan, said: al-Taqiyya is permissible until the Day of judgment.” http://www.al-islam.org/shiite-encyclopedia-ahlul-bayt-dilp-team/al-taqiyya-dissimulation-part-1#reference-4
For another article related to the topic of dissimulation, see The Divine Mission of Conversos.
Posted by Rabbi Juan Bejarano-Gutierrez, the director of the B’nei Anusim Center for Education, and author of What is Kosher?