Amulet

The Serpent Amulet of Lord British is a very mighty magical item. Its powers are many, but only the experienced user can decypher and use them. Two of its known powers are the ability to call a blue Moongate to Britannia and shed light into even the blackest darkness.

Lord British found the Amulet on Earth while he was still a youth, and it transported him to Sosaria, where he kept it with himself, always. However, when the Shadowlords abducted him before Ultima V, he lost the Amulet in the Underworld. The Avatar found it there at the graves of the fallen knights of Lord British. It was the only way to cross the darkness around the dungeon Doom. After that, it was returned to Lord British (as seen in his inventory in Ultima VI).

Trivia

 * It is possible in Ultima V to follow Lord British's Jouranal (comes with the game) to find the Amulet.