Wikipedia
Achilleus (Roman usurper)
Achilleus (fl. 3rd century AD) assumed the title of Roman emperor under Diocletian and reigned over Egypt for some time. He was possibly the Corrector of Domitius Domitianus. He seems to have succeeded the revolt started by Domitianus, after the latter died.
Achilleus was at length taken by Diocletian after a siege of eight months in Alexandria, and put to death in 298 AD.