The earliest (documented) Christian knowledge of Muhammad stems from Byzantine sources, written shortly after Muhammad's death in 632.

In the Doctrina Jacobi nuper baptizati, a dialogue between a recent Christian convert and several Jews, one participant writes that his brother "wrote to [him] saying;
that a deceiving propheth as appeared amidst the Saracens".

Another participant in the Doctrina replies about Muhammad:

"He is deceiving. For do prophets come with sword and chariot?, …

[Y]ou will discover nothing true from the said prophet except human bloodshed". [ 5 ]


One Christian who came under the early dominion of the Islamic Caliphatewas John of Damascus(c. 676–749 AD), who was familiar with Islam and Arabic. The second chapter of his book,The Fount of Wisdom, titled "Concerning Heresies", presents a series of discussions between Christians and Muslims.

John claimed that an Arian monk(whom he did not know was Bahira) influenced Muhammad and the writer viewed the Islamic doctrines as nothing more than a hodgepodge culled from the Bible.

[ 6 ]Among the first sources representing Muhammad is the polemical work "Concerning Heresy" (Perì hairéseōn) of John of Damascus, translated from Greekinto Latin. In this manuscript, the Syrian priest represents Muhammad as a "false prophet," and an " Antichrist"...


https://en.wikipedia.org/wiki/Criticism_of_Muhammad#Early_middle_ages?_e_pi_=7%2CPAGE_ID10%2C8283354513

It's so glaring even from islamic sources and the compilation of thrash he authored(qouran) that he is as fake as they come. It really beats my imagination how educated people are still falling for the fraud initiated by a stark criminal illiterate 1,437 years ago

It takes little common sense to discover islam as FALSE. But unfortunately, over a billion people believe the FALSEHOOD owing to satanic hypnotism.

truthman2012:
It takes little common sense to discover islam as FALSE. But unfortunately, over a billion people believe the FALSEHOOD owing to satanic hypnotism.

This is a testament to how powerful satan is, we should remain very prayerful as christians