Such cloaks are common in Welsh mythology; a "Mantle of Invisibility" is described in the tale Culhwch and Olwen (c. 1100) as one of King Arthur's most prized possessions.

A similar mantle appears in the Second Branch of the Mabinogi, in which it is used by Caswallawn to assassinate the seven stewards left behind by Bran the Blessed and usurp the throne.

In the folktale of the "Peach Boy" Momotarō, one of the treasures the hero collects from the ogres is a cape of invisibility, paralleling the story of Jack the giant-slayer.

[7] The Grimms clarify that Sîfrit's kappe is a cape that covers not just the head but enshrouds the body, though in later times tarnkappe came to be regarded as a cap of invisibility.

[10][11] In the original epic Nibelungenlied, the hero's cloak not only grants him invisibility, but also increases his strength, to win over the Icelandic queen Brünhild.

In Richard Wagner's opera cycle Der Ring des Nibelungen, the cloak becomes a magic helmet called the Tarnhelm, which also imparts the ability to transform upon its wearer.

[citation needed] Raoul Walsh's film The Thief of Bagdad, was released in the same year as Die Nibelungen and also features a cloak of invisibility playing a pivotal role.

[citation needed] Edgar Rice Burroughs uses the idea of an invisibility cloak in his 1931 novel A Fighting Man of Mars.

The movie Erik the Viking humorously depicts the title character using a cloak of invisibility, which he does not realize apparently works only on elderly men.

[12] Harry Potter uses a Cloak of Invisibility, that was passed down to him by his father, to sneak into forbidden areas of his school and remain unseen.

[citation needed] In The Secret History by Donna Tartt (1992), the character Richard says, "I became expert at making myself invisible"..."Sunday afternoons, my cloak of invisibility around my shoulders, I would sit in the infirmary for sometimes six hours at a time..."[citation needed] On October 19, 2006, a cloak was produced that routed microwaves of a particular frequency around a copper cylinder in a way that made them emerge almost as if there were nothing there.

Our optical cloak not only suggests that true invisibility materials are within reach, it also represents a major step towards transformation optics, opening the door to manipulating light at will for the creation of powerful new microscopes and faster computers.Furthermore, a new cloaking system was announced in the beginning of 2011 that is effective in visible light and hides macroscopic objects, i.e. objects that can be seen with the human eye.

"It looks pretty much like fiction, I do realize, but it's completely in agreement with the laws of physics," said lead researcher Vladimir Shalaev, a professor of electrical and computer engineering at Purdue.

Consequently, by a suitable choice of refractive index profile for an optical medium, light rays can be bent around and made to propagate in closed loops.