Artemidorus of Knidos (Ancient Greek: Ἀρτεμίδωρος), 1st century BC, was a native of Knidos in southwest Anatolia.

He is now best known as a minor character in Shakespeare's play Julius Caesar where, aware of the plot against Caesar's life, he attempts to warn him with a written note. Although Caesar takes the note he does not look at it before entering the Senate and shortly thereafter is assassinated. The story originates with Plutarch.^[1]

The name Artemidorus was found on an inscription at Knidos by geologist William Hamilton in the 1830s.^[2] It occurs along with the name Gaius Julius Theopompus, a friend of Julius Caesar, also mentioned by Plutarch. From the inscription, it appears that Artemidorus was the name of both the father and the son of Theopompus. G. Hirschfield ^[3] argued that Artemidorus was the son and cites a further inscription which is also discussed by C. T. Newton.^[4] This describes the honors to be given – including an altar to be built and maintained, and celebratory games – to a person whose name is unfortunately missing. However, since the games were to be called “Artemidoreia”, the likely honoree was Artemidorus.^[5]

That Artemidorus was honored in this way could be due to the tax remittance granted by Caesar to the Knidians as a reward for his families’ adherence.^[6] The Newton inscription ends by stating that the honors would be equal to those of the Gods, and Jenkins^[7] points out that Artemidorus may have been the last citizen of the Roman Republic to be made a God in his own lifetime.