Medieval Christians refused Muslim sources for knowledge of Muhammad as untrustworthy.

Evidence

In order to prove that Muhammad is indeed Antichrist, one has to know something of his biography. Alvarus and Eulogius are of course not about to ask the Muslims themselves; who would trust a life of Antichrist written by his acolytes? On the contrary, Eulogius discourages dialogue with Muslims; one must learn about the false prophet from trustworthy Christians: which is to say, for Eulogius, from Christians untainted by contact with Muslims. — John V. Tolan, Saracens, 524

Categorization

• XREF: Shows a deep medieval root of the modern Western distrust of Muslim self-description that Razack and Aziz critique in security/‘clash’ discourse — knowledge of the Other must come from within one’s own community.
• QUESTION: This refusal of Muslim-source knowledge is the seed of orientalism’s ‘Who speaks for Islam?’ problem — worth tracing how it evolves through medieval polemic into the modern expert class.