Magic Ring

A name used for Sauron's One Ring. At the time the Ring was discovered by Bilbo, deep beneath the Misty Mountains, nothing was known about it other than its power to make its wearer invisible. At that time, its nature unknown, it was considered little more than a useful trinket, a simple magical ring. During his adventures on the Quest of Erebor, Bilbo used it freely, at one time spending several weeks in an invisible state.

Sauron was at this time occupied by the assault on his fortress in the south of Mirkwood by the White Council, and by his subsequent reoccupation of Mordor. He had no suspicion, either, that his Ring might have been held by a traveller in the far northern lands, so Bilbo was fortunate that his use of the Magic Ring went unnoticed by its maker.