@Magdeleen @zleap That was Mithridates - he supposedly developed tolerance to common poisons by taking small doses on a regular basis. When he tried to commit suicide by poisoning himself - he failed, because of his tolerance.
Fun fact - I was born and raised at the foot of Mount Mithridat, located in Kerch (Crimea), where he ruled during Roman times...
I used to run up and down these steps as a kid in the summer.