Wiki: Agathodaemon

[Paul Ferguson]

"Agathodaemon (Ancient Greek: Ἀγαθοδαίμων, Agathodaímōn; c. 300) was an alchemist in late Roman Egypt, known only from fragments quoted in medieval alchemical treatises, chiefly the Anepigraphos, which refer to works of his believed to be from the 3rd century. He is primarily remembered for his various descriptions of elements and minerals, most particularly his descriptions of a method of producing silver, and of a substance he had created, which he called a 'fiery poison', and which, judging by his account, was arsenic trioxide, a highly toxic amphoteric oxide."

https://en.wikipedia.org/wiki/Agathodaemon_(alchemist)