Basilisk

Basilisk

9 min read

MythologyReligieux/seMiddle AgesMiddle Ages (5th – 15th century)

A legendary creature of the Middle Ages, the Basilisk is the king of serpents, said to kill with a single glance or its poisonous breath. It hatches from a rooster's egg incubated by a snake, and ranks among the most feared beasts in medieval bestiaries.

Frequently asked questions

The Basilisk is a legendary creature from the Middle Ages, described as the king of serpents. What you need to remember is that its name comes from the Greek basileus (king), and ancient texts, such as Isidore of Seville's Etymologies, emphasize that other serpents flee before it. What makes its title unique is that its royalty does not rely on physical strength but on a deadly power: its gaze and breath are enough to kill. In bestiaries, it is often depicted with a diadem on its head, a symbol of its monstrous sovereignty.

Key Facts

  • Described by Pliny the Elder in the 1st century in his Natural History as the king of serpents, capable of killing with its gaze
  • Taken up and elaborated in medieval bestiaries (12th – 13th century), where it became a moral and religious symbol
  • According to tradition, it hatches from a rooster's egg incubated by a snake (or a toad), symbolizing a perversion of nature
  • Its only known remedy is the gaze of a weasel, or the reflection of its own gaze in a mirror
  • Isidore of Seville described it in the 7th century in his Etymologiae, fixing its depiction for the rest of the Middle Ages

Works & Achievements

Historia Naturalis — Pliny the Elder (77 AD)

The first Western encyclopedic text to describe the Basilisk in precise detail, this monumental work in 37 books served as the primary source for all medieval descriptions of the creature.

Etymologiae — Isidore of Seville (c. 620)

The definitive encyclopedia of the Middle Ages, whose Book XII on animals codifies the properties of the Basilisk. This text was copied thousands of times and transmitted the Basilisk tradition throughout Christian Europe.

Physiologus (2nd–4th century)

An allegorical collection of Alexandrian origin that integrates the Basilisk into Christian symbolism, casting it as an embodiment of the devil and mortal sin. Translated into Latin and all the vernacular languages, it shaped medieval religious iconography.

Bestiary of Philippe de Thaon (c. 1121–1135)

The first bestiary written in a Romance language, it establishes the Basilisk's hybrid cockerel-serpent form that would become standard in Western iconography. This text helped popularize the creature beyond clerical circles.

Aberdeen Bestiary (c. 1200)

One of the best-preserved illuminated bestiaries of the Middle Ages, it contains a depiction of the Basilisk among its most finely crafted illustrations. This manuscript shows how the creature's iconography had become codified by the 13th century.

De animalibus — Albertus Magnus (c. 1260)

An encyclopedic naturalist treatise that incorporates the Basilisk into a scholastic inquiry into the nature of monstrous animals. Albertus Magnus attempts to explain the creature's properties through rational analysis, anchoring it within late medieval scholarly thought.

Anecdotes

The Basilisk is described by **Pliny the Elder** in the **1st century** as a creature no longer than twelve fingers, yet whose breath could split rocks and wither plants in its path. The medieval knights who read this shuddered: so small a beast, so great a terror.

According to medieval bestiaries, the Basilisk hatches from an egg laid by an old cock aged seven years, then incubated by a snake or a toad in a dung heap. This unnatural birth made it, in the eyes of theologians, the perfect symbol of sin giving rise to death.

The only way to kill a Basilisk without dying oneself was to hold up a mirror: upon meeting its own gaze, the creature was struck down by its own power. **Alexander the Great** supposedly used this trick, according to a late medieval legend, during the conquest of **Persia**.

The weasel was said to be the only animal naturally immune to the Basilisk's gaze. To strengthen it before battle, it was fed rue (a bitter herb). This duel between the weasel and the Basilisk appears in many illuminated bestiaries from the **12th** to the **14th century**.

In the **Middle Ages**, it was believed that the Basilisk was so venomous that if a rider pierced it with his lance, the poison would travel up the shaft of the weapon and kill both horse and man. This detail, reported by **Isidore of Seville**, made the Basilisk a metaphor for an evil that contaminates everything it touches — even from a distance.

Primary Sources

Historia Naturalis (Natural History) (c. AD 77)
The basilisk is a serpent from the province of Cyrene, at most twelve fingers in length. It bears a white marking on its head in the shape of a diadem. It kills shrubs with its breath, scorches grass, and shatters rocks: such is its deadly power.
Etymologiae (Etymologies), Book XII (c. AD 620)
The basilisk is called the king of serpents, for all others flee before it. It kills with its gaze, and it kills also with its breath; and if a man on horseback strikes it with a lance, the venom travels up through the wood and kills the rider.
Physiologus (2nd–4th century AD)
The Basilisk is the most fearsome of all creatures; its gaze alone is enough to kill; it reigns over all serpents as a king over his subjects, and no herb grows where it has passed.
Liber de natura rerum (Book on the Nature of Things) (c. 1240)
The weasel alone is immune to the Basilisk; it attacks and puts it to flight, and to do so it eats rue before the battle, for this herb fortifies it against the basilisk's venom.
Bestiary of Philippe de Thaon (c. 1121–1135)
The basilisk has the form of a cockerel down to the waist, and then that of a serpent; it kills by gaze and by breath, and none can withstand it save the weasel by its nature.

Key Places

Cyrene (Cyrenaica, ancient Libya)

A region of North Africa identified by Pliny the Elder as the birthplace of the Basilisk. Its rocky, sandy desert seemed to the ancients the ideal setting for a creature capable of desiccating all life.

The Libyan Desert

An arid expanse mythologized by ancient and medieval authors as the domain of the Basilisk. Its barrenness was attributed to the creature's passing — its breath scorching vegetation and poisoning springs.

Monastic scriptoria (England, France, 12th–14th century)

It was in the copying workshops of abbeys (Canterbury, Saint Albans, Paris) that illuminators gave the Basilisk its definitive iconographic form: a winged cockerel with a serpent's tail, immortalized in hundreds of manuscripts.

Alexandria (Egypt)

The intellectual birthplace of the *Physiologus*, the allegorical zoological text that established the Basilisk as a Christian symbol of evil. The Alexandrian library and philosophical circles transmitted this tradition throughout the medieval world.

See also