1. **Hippocratic Corpus**: In the Hippocratic text "On the …

1. **Hippocratic Corpus**: In the Hippocratic text "On the Sacred Disease" ( Peri Hires Nousou), the author discusses the concept of "phantasma" (φάντασμα) in relation to epilepsy and other neurological disorders. The text describes how patients may experience hallucinations or illusions due to an imbalance of bodily humors.
2. **Galen's works**: The Greek physician Galen (129-216 CE) wrote extensively on the topic of perception and illusion in his medical texts. In his treatise "On the Natural Faculties" (De Naturalibus Facultatibus), Galen discusses how the brain can be deceived by false impressions, leading to perceptual errors and illusions.
3. **Aretaeus of Cappadocia's "On the Causes and Symptoms of Chronic Diseases"**: In this text, Aretaeus (c. 81-131 CE) describes a condition called "phantasiakon" (φαντασιακόν), which refers to a type of hallucination or illusion that can occur in patients with mental or physical disorders.