In tenth and eleventh-century Syria there lived a blind poet called Al-Ma'arri.
He became well known for a poetry that was affected by a "pervasive pessimism." He labeled religions in general as "noxious weeds" and said that Islam does not have a monopoly on truth.
He had particular contempt for the ulema, writing that: They recite their sacred books, although the fact informs me that these are fiction from first to last. Then perish the fools who forged the religious traditions or interpreted them!
In 1280, the Jewish philosopher, Ibn Kammuna, criticized Islam in his book Examination of the Three Faiths.
Islam's sensual descriptions of paradise led many Christians to conclude that Islam was not a spiritual religion, but a material one.
Although sensual pleasure was also present in early Christianity, as seen in the writings of Irenaeus, the doctrines of the former Manichaean Augustine of Hippo led to broad repudiation of bodily pleasure in both life and the afterlife.
Maimonides criticised what he perceived as the lack of virtue in the way Muslims rule their societies and relate to one another.
Apologetic writings, attributed to Abdullah Ibn al-Muqaffa, not only defended Manichaeism against Islam, but also criticized the Islamic concept of God.
This article needs editing for compliance with Wikipedia's Manual of Style.
In particular, it has problems with This article consists primary of lists, quoting persons, who spoke against Islam, without providing further contexts and does not explain that exactly is critisized. Another criticism focuses on the question of human rights in the Islamic world, both historically and in modern Islamic nations, including the treatment of women, LGBT people, and religious and ethnic minorities, as evinced in Islamic law and practice.