Voltaire, Rousseau, Henri de Boulainvilliers and Napoleon all commented on Prophet Muhammad. The Enlightenment in France had changed the way they thought of him.
Islamic scholars have traditionally categorized the enemies of Islam during the time of Prophet Muhammad (salAllahu alayhi wa sallam) into two categories. The first are those who vehemently opposed Islam, to the point where they were willing to sacrifice their own pre-Islamic values in their efforts to put down Prophet Muhammad, his followers, and his mission.
In this category one may find, for example, Abu Jahl ibn Hishām or Umayyah ibn Khalaf, and they along with many others in this category perished in the Battle of Badr. But in the second category were those who opposed Islam and persecuted/fought the Muslims but they remained noble in character and held on to certain admirable pre-Islamic values, not trampling all over them in trying to subdue the Islamic movement.
In this category one may find, for example, Khālid ibn al-Walīd or ‘Amr ibn al-‘Ās, and even ‘Umar ibn al-Khattāb (radiAllahu anhum ajma‘īn). It is noteworthy that Allah (subhānahu wa ta‘āla) eventually guided most, if not all, of the people in this category to Islam. 
Another area of historical study where this categorization of the opponents of Islam can be applied is in the perception of Prophet Muhammad (salAllahu alayhi wa sallam) in European intellectual thought.
For most of European history after the dawn of Islam, Prophet Muhammad has been demonized by Christian scholars, including the famous reformer Martin Luther, for example. This has not been because a critical understanding of the Prophet’s life was achieved by European intellectuals – for the most part, they didn’t even try.
Thus, more often than not it was preferable to them (and “they” at this time was the Roman Catholic Church) to utterly demonize Prophet Muhammad, because by doing so they could pinpoint him as the man who embodied everything that they, as Christians living the tough life in medieval Europe, ought to hate about the Muslims, be they Muslims in Spain, Sicily, or Anatolia.
By the 18th century, however, the situation had changed drastically. Muslims were no longer the rulers of Spain or Sicily, and even in Anatolia the power of the once feared Ottoman Empire was starting to decline. But even more importantly, the Renaissance (c. 14th-17th centuries) and Protestant Reformation (c. 1517-1648) had occurred in Europe, leaving the Roman Catholic Church with a lot less influence over the European population than it once had.
Intellectuals could now independently challenge beliefs that had been unquestioned in European society for centuries, and the long-held negative perception of Prophet Muhammad (salAllahu alayhi wa sallam) in Europe finally began to be challenged as well. This period of intellectual rethinking came to be known as the Age of Enlightenment (c. 1620s-1780s), and was particularly popular in France (where it would culminate in the French Revolution in 1789).
Henri de Boulainvilliers
Henri de Boulainvilliers (1658-1722) was a French nobleman and historian, inspired by the famous philosophers René Descartes and John Locke, and an Enlightenment-era intellectual who wrote on physics, philosophy, theology and, of course, on history.
In one of his more famous works, titled Vie de Mahomed (The World of Muhammad), he defended Prophet Muhammad against common allegations that he was inspired by a Christian assistant, that his doctrine was irrational, and that he was an imposter.
Instead, Henri argued, Muhammad was a divinely-inspired messenger whom God had sent to liberate the Near East from the despotic rule of the Romans and Persians and to spread the message of tawhīd, or God’s indivisible unity, from India to Spain. Muhammad’s success, said Henri, was such that it “could only be from God.”
About Islam, Henri said that Muhammad’s doctrine merely removed all that was irrational and undesirable about Christianity as it was practiced at the time. Muhammad “seems to have adopted and embraced all that is most marvelous in Christianity itself,” wrote Henri, “so that what he retrenched, relates obviously to those abuses alone, which it was impossible he should not condemn.”
Henri de Boulainvilliers’ work was banned in Catholic France but was published in 1730, after his death, in Protestant Amsterdam and London. 
French philosopher Voltaire
Henri de Boulainvilliers’ historical representation of Prophet Muhammad (salAllahu alayhi wa sallam) had an effect on other Enlightenment-era thinkers, particularly the French philosopher Voltaire (1694-1778).
Voltaire, a renowned poet, essayist, playwright and also a historian, is most famous for his attacks on the established Roman Catholic Church, his advocacy of freedom of religion and of expression, and his advocacy of secularism. His opposition to Islam and his demonization of Prophet Muhammad, however, was carried out even more vehemently than his attacks on the Church and the Pope.
In 1736, he wrote a play called Le Fanatisme, ou Mahomet le Prophete (Fanaticism, or Muhammad the Prophet) and it was first staged in 1741. As the name suggests, it portrayed the Prophet as “an impostor desiring self-glorification and beautiful women who is willing to lie, to kill, and even to wage war against his homeland to get what he desires.”  He expressed similar views about the Prophet in two of his letters, one to Frederick II of Prussia in 1740 and the other to Pope Benedict XIV in 1745.
Sometime after 1745, however, he read Boulainvilliers’ Vie de Mahomed, and it seems to have had a lasting impact on his perception of Prophet Muhammad (salAllahu alayhi wa sallam). Later in life, particularly in his historical writings such as the Essay on the Customs and the Spirit of the Nations (1756), Voltaire praised the Prophet as an effective and tolerant leader and a successful conqueror, though he still maintained that Prophet Muhammad was not divinely inspired but was “so carried away [by his success as a leader] that he believed himself inspired by God.” 
Jean-Jacques Rousseau (1712-1778) was yet another Enlightenment-era French philosopher who couldn’t help but comment on Prophet Muhammad (salAllahu alayhi wa sallam), and that too in his magnum opus, The Social Contract (1762). Muhammad, he said, was neither an imposter nor a sorcerer, but an admirable legislator who successfully combined spiritual and worldly power. 
In 1787, Claude-Emmanuel Pastoret (1755-c. 1830), a French author and politician, published his Zoroaster, Confucius and Muhammad, in which he compared and contrasted the careers of the three Eastern religious “great men”, “the greatest legislators of the universe.” He defended Prophet Muhammad against the allegations commonly made against him, and praised the Qur‘ān for the way it upholds the unity of God (tawhīd). 
In part two, you’ll learn about Napoleon Bonaparte’s opinion on Prophet Muhammad (PBUH) and how the the French leader admired the messenger of Allah. Stay tuned..
- Yasir Qadhi, “Seerah of Prophet Muhammed 3 – Why study the Seerah? & Pre-Islamic Arabia”, YouTube video, June 22, 2012,https://www.youtube.com/watch?v=4F5qzMI2IKs.
- Henri de Boulainvilliers,La vie de Mahomed (Amsterdam: P. Humbert, 1730); Boulainvilliers, The Life of Mahomet (London: W. Hinchliffe, 1731), 179-222.
- John Tolan, “European Accounts of Muhammad’s Life”, in Jonathan Brockopp (Ed.),The Cambridge Companion to Muhammad (New York: Cambridge University Press, 2010), 241.
- Voltaire,Essai sur les moeurs, chap. 6.
- Jean-Jacques Rousseau,Du contrat social (Amsterdam: Marc Michel Rey, 1762), 303–304.
- Emmanuel Pastoret,Zoroastre, Confucius et Mahomet, comparés comme sectaires, législateurs, et moralistes; avec le tableau de leurs dogmes, de leurs lois et de leur morale (Paris: Buisson, 1787), 385, l. 1 and 234-236.
Originally posted on ihistory.co