Pyrrho (ca. 360 BC – ca. 270 BC), a Greek philosopher of classical antiquity, is credited as being the first Skeptic philosopher and the inspiration for the school known as Pyrrhonism, founded by Aenesidemus in the 1st century BC.
1.) Adrian Kuzminski (2008). Pyrrhonism: How the Ancient Greeks Reinvented Buddhism. Lexington Books. pp. 41-42. ISBN 9780739125069. "In particular, Flintoff notes the similarity between Pyrrho's agnosticism and suspension of judgment and the Buddha's refusal to countenance beliefs about the nature of things, including his insistence that such beliefs were to be neither affirmed nor denied."
2.) Don E. Marietta (1998). Introduction to Ancient Philosophy. M.E. Sharpe. p. 162. ISBN 9780765602169. "Pyrrho advocated agnosticism and suspension of judgment about the nature of the world. His Skepticism also applied to matters of ethics; he held that nothing is just or honorable by its nature."