according to fable, may be obtained in a multitude of ways. For example:
A chamelon carried in the breast will render a person invisible.
A capon stone, called “Alectoria,” will render any person invisible who carries it about his person. (See Mirror Of Stones.)
A dead hand. It is believed that a candle placed in a dead man's hand gives no light to any but those who use it. (See Hand.)
The helmet of Perseus (2 syl.) and the helmet of Pluto (called Orci Galea) both rendered the wearer invisible. (Classic story.)
The helmet which Pluto gave to the Cyclops made them invisible whenever it was worn.
The Moros Musphoron was a girdle of invisibility. (Mrs. Centlivre: A Bold Stroke for a Wife.
Otnit's ring. The ring of Otnit, King of Lombardy, according to the Heldenbuch, possessed a similar charm. Reynard's wonderful ring had three colours, one of which (the green) caused the wearer to become invisible. (Reynard the Fox, 1498.)
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894