Caption: The Death of Socrates (1787) by Jacques-Louis David (1748--1825).

The scene, from the Phaedo of Plato (428/427--348/347 BCE), shows Socrates (c.469--399 BCE)---in a state of heroic nudity---about to drink poison hemlock.

Socrates counts as a Presocratic philosopher because of his early interest in natural philosophy (and that he wrote nothing at all) and is ex officio a "Socratic philosopher".

Credit/Permission: Jacques-Louis David (1748--1825), 1787 (uploaded to Wikipedia by User:Didactohedron, 2004) / Public domain.
Image link: Wikipedia: File:David - The Death of Socrates.jpg.
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File: Ancient Astronomy file: socrates_death.html.