Much of what medieval Europe believed was Aristotle was actually pseudepigrapha by other authors

Evidence

A great deal of what they translated was not by Aristotle but was drafted by other, crazier hands. Among the many pseudepigrapha that were claimed to be by Aristotle were a Neoplatonist Theology, an alchemical treatise, On the Twelve Waters of the Secret River, an astrological Book on the Properties of the Elements and of the Planets, and above all the Secreta Secretorum (‘Secret of Secrets’), which, before being translated into Latin, had circulated widely in the Arabworld under the title Sirr al-Asrar. In Europe too it became a popular and influential work and more than two hundred manuscripts of the Latin version have survived. The Secreta Secretorum, which originally was put together in Syriac in the eighth century, is an encyclopedic treatise that deals with politics, ethics and medicine, but it also put forward astrological notions, and a belief in the occult virtues of plants and stones pervades its treatment of many subjects. — Robert Irwin, For Lust of Knowing, 67

Categorization

• XREF: Connects to the theme of how authority and misattribution shape knowledge transmission — parallels earlier chapters’ treatment of how institutions carry forward errors.
• SEED: Potential essay angle: how the fake ‘Secret of Secrets’ outsold genuine ancient philosophy in Europe, and modern equivalents of authoritative misattribution (urban legends cited to experts).