"Asp" is the modern anglicisation of the word "aspis", which in antiquity referred to any one of several venomous snake species found in the Nile region. The specific epithet, aspis, is a Greek word that means "viper". It is believed that aspis referred to what is now known as the Egyptian cobra.
Throughout dynastic and Roman Egypt, the asp was a symbol of royalty. Moreover, in both Egypt and Greece, its potent venom made it useful as a means of execution for criminals who were thought deserving of a more dignified death than that of typical executions.
In some stories of Perseus, after killing Medusa, the hero used winged sandals to transport her head to King Polydectes. As he was flying over Egypt, some of her blood fell to the ground, which spawned asps and amphisbaena.
According to Plutarch, Cleopatra tested various deadly poisons on condemned people and concluded that the bite of the asp (from aspis—Egyptian cobra, not European asp) was the least terrible way to die; the venom brought sleepiness and heaviness without spasms of pain. The asp is perhaps most famous for its alleged role in Cleopatra's suicide after Mark Antony (her husband) killed himself by falling on his sword due to a false report of Cleopatra killing herself. Some believe it to have been a horned viper, though in 2010, German historian Christoph Schaefer and toxicologist Dietrich Mebs, after extensive study into the event, came to the conclusion that rather than enticing a venomous animal to bite her, Cleopatra actually used a mixture of hemlock, wolfsbane and opium to end her life.
Nonetheless, the image of suicide-by-asp has become inextricably connected with Cleopatra, as immortalized by William Shakespeare:
With thy sharp teeth this knot intrinsicate
Of life at once untie: poor venomous fool
Be angry, and dispatch.
- —Cleopatra, Act V, scene II
- Antony and Cleopatra
The hypnalis is a legendary creature described in medieval bestiaries. It is described as a type of asp that kills its victim in their sleep. "Cleopatra placed it on herself (at her breasts) and thus was freed by death as if by sleep."
- Shorter Oxford English Dictionary. Oxford, UK: Oxford University Press. 2007. ISBN 978-0199206872.
- Gotch AF. 1986. Reptiles – Their Latin Names Explained. Poole, UK: Blandford Press. 176 pp. ISBN 0-7137-1704-1.
- Schneemann, M.; R. Cathomas; S.T. Laidlaw; A.M. El Nahas; R.D.G. Theakston; D.A. Warrell (August 2004). "Life-threatening envenoming by the Saharan horned viper (Cerastes cerastes) causing micro-angiopathic haemolysis, coagulopathy and acute renal failure: clinical cases and review". QJM: An International Journal of Medicine. 97 (11): 717–27. doi:10.1093/qjmed/hch118. PMID 15496528.
Whether Cleopatra used a snake as the instrument of her suicide has been long debated. Some favour the idea that she chose C. cerastes, but its venom is insufficiently potent, rapid and reliable. A more plausible candidate is the Egyptian cobra or 'asp' (Naja haje).
- "Battle of Actium (31 B.C.)". The Greenhaven Encyclopedia of Ancient Greece. Don Nardo. Ed. Robert B. Kebric. Detroit: Greenhaven Press, 2007. 71-72. World History in Context. Web. 30 Mar. 2016.\
- Lucan, Pharisaical, (c.61-65), trans. Robert Graves, book IX
- Crawford, Amy (April 1, 2007). "Who Was Cleopatra? Mythology, propaganda, Liz Taylor and the real Queen of the Nile". Smithsonian.com. Retrieved 4 September 2009.
- Kinghorn, A. M. (March 1994). "'All joy o' the worm' or, death by asp or asps unknown in act v of Antony and Cleopatra". English Studies. 75 (2): 104–9. doi:10.1080/00138389408598902.
The venomous reptile commonly known today as 'Cleopatra's asp' is a Cobra (Cerastes cornutus)
- Melissa Gray (2010-06-30). "Poison, not snake, killed Cleopatra, scholar says - Cleopatra died a quiet and pain free death, historian alleges". CNN. Archived from the original on 2012-09-12. Retrieved 2012-04-13.
-  Early Christians and Animals: By Robert McQueen Grant (p.139)]
- Clark, Willene B. (2006). A Medieval Book of Beasts: The Second-family Bestiary : Commentary, Art, Text and Translation. Boydell Press. p. 198. ISBN 9780851156828. Retrieved 25 August 2020.