Christian polemicists preferred a fabricated teaching monk over Muslim claims of miracle

Evidence

Ricoldo, to whom alternative versions were certainly available, accepted the opinion that Muhammad was illiterate. San Pedro pointed out that a Muslim who did not hold Muhammad to have been uneducated was a heretic in his own religion; without persuading himself that all the details of the ‘Christian’ version of the monk who taught Muhammad, which he recounted, were true, he was reasonably sure that Muhammad would have needed to be taught such erudite matters as the history of the Seven Sleepers of Ephesus. — Norman Daniel, Islam and the West, 488

Categorization

• XREF: The fabricated ‘monk taught Muhammad’ claim is a medieval ancestor of the modern geneaology-inversion that the vault traces — the West’s constitutive outside must have been authored by the West’s own religious tradition.
• QUESTION: Who first fully traced the Bahira/Sergius the monk legend and how it travelled over centuries? Worth chasing for a concrete genealogy.