According to Plutarch

Plutarch

Plutarch then named, on his becoming a Roman citizen, Lucius Mestrius Plutarchus , c. 46 – 120 AD, was a Greek historian, biographer, essayist, and Middle Platonist known primarily for his Parallel Lives and Moralia...

, Hagnothemis was the authority upon which rested the belief that Antipater

Antipater

Antipater was a Macedonian general and a supporter of kings Philip II of Macedon and Alexander the Great. In 320 BC, he became Regent of all of Alexander's Empire. Antipater was one of the sons of a Macedonian nobleman called Iollas or Iolaus and his family were distant collateral relatives to the...

 poison

Poison

In the context of biology, poisons are substances that can cause disturbances to organisms, usually by chemical reaction or other activity on the molecular scale, when a sufficient quantity is absorbed by an organism....

ed Alexander the Great, after he had heard King Antigonus

Antigonus I Monophthalmus

Antigonus I Monophthalmus , son of Philip from Elimeia, was a Macedonian nobleman, general, and satrap under Alexander the Great. During his early life he served under Philip II, and he was a major figure in the Wars of the Diadochi after Alexander's death, declaring himself king in 306 BC and...

 speak of it. Plutarch gives no further biographical details for Hagnothemis, but he does state that, according to his account, Antipater undertook the assassination

Assassination

To carry out an assassination is "to murder by a sudden and/or secret attack, often for political reasons." Alternatively, assassination may be defined as "the act of deliberately killing someone, especially a public figure, usually for hire or for political reasons."An assassination may be...

 at Aristotle

Aristotle

Aristotle was a Greek philosopher and polymath, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, linguistics, politics, government, ethics, biology, and zoology...

's instigation, and that it was Aristotle who procured the poison. Graham Phillips

Graham Phillips (author)

Graham Phillips is a British author and historical mysteries researcher. Phillips has a background working as a reporter for BBC radio and a magazine editor...

, in his investigation into Alexander's alleged murder, has speculated that it may have been Hagnothemis' testimony that so convinced Alexander's mother Olympias

Olympias

Olympias was a Greek princess of Epirus, daughter of king Neoptolemus I of Epirus, the fourth wife of the king of Macedonia, Philip II, and mother of Alexander the Great...

that her son had not died of natural causes.