Muhammad pictures
Various depictions of Muhammad, the apocryphal founder of Islam, the Arabian branch of Egyptian mythology.
In religio-mythology, Muhammad (569 to 632 ACM | Purported) (CR:61), aka "Mahomet" (Volney, 1791), the said-to-have-been 71st generation descendant of Abraham, purported author of the Quran, the main book of Islam, said to have existed from , is []

Overview
In c.710, Bede, supposedly (Ѻ) influenced by John of Damascus, is said to have written about Muhammad.

Religio-mythology
In 1923, Ameer Ali, in his A Critical Examination of the Life and Teachings of Mohammad, made some loose connections between the newly-formed Islam and Egyptian mythology, e.g. Osiris. [7]

In 2006, Natan Yoel, in his Moon-o-theism, citing Ali, cited Plutarch (c.110AD) as referring to Osiris as a moon god, then cites Budge:

“Osiris-Aah, i.e. Osiris the moon god, appears in the form of a human-headed mummy, with a crescent-moon and full moon on his head. In his hands he holds symbols of stability, life, serenity, power and dominion.”
— Wallis Budge (1911), Osiris and the Egyptian Resurrection, Volume One (pg. 59)

Giving the following images:

Osiris as moon god

Yoel then concluded as follows:

“Muhammad thought of Christian Trinity, not as ‘father’, ‘son’, and ‘spirit’, but as a triad of father Osiris, sun Horus, and mother Isis.”
— Yoel Natan (2006), Moon-o-theism (pg. 608)

In 2012, Brett Stortroen, in his Mecca, Muhammad & the Moon-god: a Candid Investigation into the Origins of Islam, argued that the Quran was constructed as follows:

“Ancient Arabian folklore with its stone and astral cults, shamanism, various Judaic traditions, heretical sects within Christianity, and prevalent moon-god veneration, were all rolled together into a kind of salad religion, taking bits and pieces [from surrounding religions].”

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Non-Existent?
See main: Muhammad never existed
In 1239, Frederick II published a treatise that denied the divinity of Jesus, Moses, and Muhammad, declaring each of them imposters, but conducted experiments to test the truths of various religious models, e.g. that Adam and Eve were the first two humans (language deprivation experiments) and soul detection experiments.

In 1930, Soviet Marxist theoretician Liutsian I. Klimovich, in his lecture “Did Muhammad Exist?”, argued the time gap between Muhammad’s alleged lifetime and the first written sources was so huge that we cannot suppose that any of the information given in these sources is authentic; that nothing is known for sure about the historical Muhammad, and that it is even likely that he never existed. Quite consequently, Klimovich assumed that the Koran was not Muhammad’s work but the product of a whole group of authors. Muhammad was created by later historians as a myth, designed to explain the emergence of the Islamic community out of the Hanif movement. The prophet was an invention to cover up early Islam’s character as a social protest movement. [4]

In 2003, Walter Williams, in his The Historical Origin of Islam, asserted that Muhammad is the brainchild of Arabian scholar Ibn Arabi (1165-1240) (Ѻ) who was the main individual involved in the morphing and mythologizing (Ѻ) of the making of the prophet Muhammad; he also shows that the the Koran is a mixture of Jewish literature, put together by Jewish scholars to include the Torah and the New Testament Gospels. [6]

Arab power
Above, a section from John Spark's histomap (1932), shows the rise and fall of "Arab power", from 450-850AD, during which time Islam was invented, similar to rise and fall of "Roman power", from 250BC-300AD, during which time Christianity was invented, which gives indication as to when the figure of Muhammad was invented (c.750AD), similar to the way the character of Jesus was invented (c.200AD). [5] All world powers, in short, arise out of some form of heated "action" to explode into the form that they become in history; the legare or "glue" of the why of the action, therein, becomes and afterthought, and named the "religion" of the movement, albeit done after the peak of the power.
In 2008, German jurist and former Islamic theologian Sven Kalisch, whose doctoral thesis (1997) was on “common sense and flexibility in Islamic legal methodology” (see also: Goethe's jurisprudence issues and student reactions), completed at the Faculty of Law and Economics at the Technical University of Darmstadt—a Protestant-to-Muslim convert (age 15) turned Muslim-to-nonbeliever convert (age 44)—made controversial headlines by stating, in an article entitled “Islamic Theology Without the Historic Muhammad: Comments on the Challenges of the Historical-Critical Method for Islamic Thinking”, his researched opinion that Muhammad never existed; at the time, he was said to be in the middle of completing a book on this subject. [1]

In 2011, Hans Jansen, in his “The Historicity of Muhammad, Aisha and Who Knows Who Else”, argued the position that Muhammad is a fictional character. [3]

In 2012, Robert Spencer, founder (Ѻ) of JihadWatch.org (Ѻ), in his Did Muhammad Exist?: An Inquiry into Islam's Obscure Origins, asserted, per reason that there is no mention of a person named "Muhammad" in Arab literature until 692, a full sixty years (Ѻ) AFTER the purported death of Muhammad in 632, that what is Islamic revelation was an afterthought, a narrative created after the Arab conquests of the Near East, to give the new ruling elite an ideological pretext for power. [2]

Quotes
The following are noted quotes:

“That Muhammad could predict certain events does not prove that he was a prophet: he may have been able to guess successfully, but this does not mean that he had real knowledge of the future. And certainly the fact that he was able to recount events from the past does not prove that he was a prophet, because he could have read about those events in the Bible and, if he was illiterate, he could still have had the Old Testament read to him.”
Abu al-Warraq (c.860) [1]

Muhammad’s own presuppositions and systems show that religious traditions are not trustworthy. The Jews and Christians say that Jesus really died, but the Quran [Surah 4:157] contradicts them.”
Ibn al-Rawandi (c.870) (Ѻ)

Frederick II, this pestilent king, a scorpion spitting out poison from the stinger of his tail, has notably and openly stated that—in his own words—the whole world has been fooled by three imposters, Jesus Christ, Moses, and Muhammad, two of whom died honorably, while Jesus himself died on the cross. Moreover, he has dared to affirm, or rather, he has fraudulently claimed, that all those who believe that a virgin could give birth to the god who created nature, and all the rest, were fools. And Fredrick has aggravated the heresy by this insane assertion, according to which no one can be born without having been conceived by the prior intercourse of a man and woman; he also claims that people ought to believe nothing that cannot be proven by the strength and reason of nature.”
— Pope Gregory IX (1239), address to monarchs

Muhammad probably never existed.”
— Sven Kalish (2008) (Ѻ)

“It may sound crazy but it is not as crazy as it sounds: a number of scholars consequently suspect that Muhammad is not a historical figure, but a literary character that was created by ancient Arab storytellers, perhaps early in the eighth century of our era.”
— Hans Jansen (2011), “The Historicity of Muhammad” [3]

References
1. (a) Kalisch, Sven. (2008). “Islamic Theology Without the Historic Muhammad: Comments on the Challenges of the Historical-Critical Method for Islamic Thinking”, (in German), Publication.
(b) Anon. (2008). “Excerpt: Muslim Academic Questions Muhammad’s Existence”, The Wall Street Journal, Nov. 15.
(c) Higgins, Andrew. (2008). “Professor Hired for Outreach to Muslims Delivers a Jolt” (Ѻ), The Wall Street Journal, Nov. 15.
(e) Historicity of Muhammad – Wikipedia.
(f) Thims, Libb. (2011). Purpose? (in a Godless universe). (94-pg manuscript) (unfinished); Online as 105-page unfinished manuscript (14 Apr 2013). IoHT publications.
(g) Sven Kalisch – WikiIslam.net.
(h) Sven Kalisch (German → English) – Wikipedia.
2. (a) Spencer, Robert. (2007). The Truth About Muhammad (Ѻ). Publisher.
(b) Spencer, Robert. (2012). Did Muhammad Exist?: An Inquiry into Islam's Obscure Origins (foreword: Ibn Warraq). Open Road Media.
(c) Zmirack, John. (2012). “Amazon Review” (Ѻ), Apr 9.
3. Jansen, Hans. (2011). “The Historicity of Muhammad, Aisha and Who Knows Who Else” (Ѻ), Trykkefrihed.dk, May 16.
4. (a) Existence of Muhammad (section) – Wikipedia.
(b) Klimovich, Liutsian. (1931). “Did Mohammed exist? The debate in the Communist Academy in anti-religious section of the Institute 12/1930 CI philosophy. on the report of LI Klimovich” (“Sushchestvoval li Mokhammed? Diskussiia v Kommunisticheskoi akademii v antireligioznoi sektsii instituta filosofii 12/XI 1930g. po dokladu L.I. Klimovicha”), in: Voinstvuiushchii ateizm, No. 2-3, (1931), 189-218.
5. Sparks, John. (1932). “Histogram” (Ѻ), Slate.com.
6. Williams, Walter. (2003). The Historical Origin of Islam (abs). Maathian Press.
7. Ali, Syed Ameer. (1923). A Critical Examination of the Life and Teachings of Mohammad (retitled: The Spirit of Islam: a History of the Evolution of Ideals of Islam with a Life of the Prophet) (Osiris, 5+ pgs). Cosimo, 2010.
8. Natan, Yoel. (2006). Moon-o-theism, Volume One of Two (Osiris, 5+ pgs; quote, pg. 608). Publisher.
9. Stortroen, Brett. (2012). Mecca, Muhammad & the Moon-god: a Candid Investigation into the Origins of Islam (editor: Gene Beach) (Amz). Publisher.

Further reading
● Price, Robert M. (2017). Atheism and Faithism (§: Myths and Men, III. Muhammad, pgs. 143-). Publisher.

External links
Muhammad – Wikipedia.
Muhammad (name) – Wikipedia.

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