Maimonides further explains his view regarding Islam in a letter that he wrote to a certain Ovadiyah the Proselyte, who, having previously been a Muslim, certainly knew the particulars of the religion, and had declared that it was not idolatry. Because of his opinion, he was repremanded by his teacher, who claimed that the Islamic religious service at Mecca was idolatrous in that it involved the ritual of throwing stones which constituted worship of ''Merkulius.'' The identification of Islamic worship at Mecca with an idolatrous cult of Merkulius was very common in the Middle Ages, see R. Asher ben Yehiel.<ref>R. Asher ben Yehiel's Teshuvot [Jerusalem, 1981], 5:2</ref> Regarding this responsum, see Isaac Herzog, Pesakim u-Khetavim<ref>R. Isaac Herzog, Pesakim u-Khetavim [Jerusalem, 1990], vol. 4, no. 49</ref>. Historians have claimed, but offered no evidence, for the contention that some Jewish scholars were influenced by Christian notions that also identified the idolatrous worship of Merkulius with the Islamic worship at Mecca.<ref>See Jose Faur 's ''Iyyunim ba-Mishneh Torah le-ha-Rambam'' (Jerusalem, 1978), p. 236, note 54. This has been analyzed at great length by Bernard Septimus, see bibliography</ref>
However Maimonides' supported Ovadiyah over his teacher.