Codex Coin

The Codex Coin is a item of great power.

Description
Not only is this coin capable to be sent to other worlds, but it also has the power to call the blue moongate to Britannia and scare away dark powers. It appears in Ultima V. Made by the Royal Coinmaker Sir Arbuthnot at the orders of Iolo and Shamino, it was sent to Earth to summon the Avatar at the beginning of  Warriors of Destiny. It was the last idea they had to topple Lord Blackthorn's regime. The Avatar used it together with the ankh amulet to open the moongate and later to scare away the Shadowlords. The coin strangely was never seen again after this event.

The Codex Coin as Trinket
In the original release of Ultima V, the Codex Coin was included in the game box. It was a real coin made of metal, exactly like the one in the game. The coin also was included in the special edition of the Ultima Trilogy II compilation as one of the possible trinkets.

Ultima V: Lazarus
In the Ultima V: Lazarus remake, the coin doesn't vanish and stays in the inventory. It is later is used to prove the Avatar's identity to Sir Arbuthnot at Greyhaven. He also gives the Avatar a much more detailed story on the creation of the coin.

Trivia

 * This trinket was inspired by a coin presented to Richard Garriott with the codex symbol on one side and the Bell of Courage, Book of Truth and Candle of Love which was minted by Bill Jensen (a.k.a. Arbuthnot Dragon).