Codex of Ultimate Wisdom

The Codex of Ultimate Wisdom is a magical book, bound in leather and gold, that incorporates all knowledge that exists. It is said it holds the "one right and true answer to any question." When a reader approaches the book it is always open to the page they seek, and they are always able to read it despite their language. Emblazoned on the cover is the symbol of the Codex, a set of six lines and two circles arranged to touch three central circles in different manners. This symbol represents the eight virtues and three core principles of Britannian and Gargish virtue, which the Codex inspired.

The origins of the Codex are unknown. It was first found floating in the Void by the Gargish seer Naxatilor.

For a long time, the Codex was in possession of the Gargoyles. It was they, through their seer Naxatilor, who had managed to draw it from the Void with the aid of the Concave Lens, Convex Lens and Vortex Cube. The Gargoyles kept it in the Shrine of Singularity at the bottom of the Abyss. In Ultima IV the Codex was discovered by the Stranger. The magical book tested The Stranger on the Britannian Virtues, then pronounced him/her The Avatar. Following the discovery, the Great Council managed to draw the Codex into Britannia. This action unwittingly caused massive destruction to the Gargoyle race and collapsed much of the Underworld in the end.

The Shrine of the Codex was built over the entrance of the Abyss, the new home of the Codex. Two giant, enchanted stone statues called the Stone Guardians stand athwart the path leading into the shrine, which from Ultima V to Ultima VI would only allow people on sacred quests to pass and read the Codex. The origins of these statues are never stated, but it's possible they were created by the Great Council.

The Codex became a symbol of conflict in Ultima VI. Humans and Gargoyles alike claimed it for themselves. Thus, the Avatar used two special lenses and the Vortex Cube, to return the Codex to the Void. Each side could still read the Codex with their lens, but none could claim it as their possession anymore.

In Ultima IX, the Codex returned to Britannia without explanation, and the working of the lenses was also altered.

The Codex Symbol
The Codex Symbol, called this because it is on the cover of the Codex of Ultimate Wisdom, is an simple but very clear way to show how the Eight Virtues are founded on the three principles of Truth, Love and Courage, by assigning each principle a color, and each virtue is a mix of the colors of the principles the virtue is based on.

First there are the three circles of the three principles of Truth, Love and Courage, which are the foundations of all the virtues (with exception of Humility).

Then come the Virtues of Honesty, Compassion and Valor, forming a triangle around the three circles. Each of the three lines only touch one circle, since these virtues are only founded on one principle. Therefore, the three lines have the same colors as the three circles.

Then come three more lines, which roughly form a headstand triangle. These represent the virtues of Justice, Sacrifice and Honor. Since each line touches two circles, because these virtues base each on two principles, they mix the colors, resulting in green, orange and purple.

The small circle in the center is the virtue of Spirituality. It touches all three circles, since the virtue is based on all three principles. All three colors mix into white.

The outer circle represents the Virtue of Humility. Since it is independent of the principles, it touches no circle, it has no color, and is therefore black.

Codex Messages in Ultima V
The following are messages The Avatar reads from the Codex in Ultima V, in response to the quests ordained by the Shrines of Virtue:

Honesty: "A dishonest life brings unto thee temporary gain, but forsakes the permanent."

Compassion: "Only a detested life owes its pleasures to another's pain."

Valor: "Those who fear to try, know not their limits and thus know not themselves."

Justice: "Those who inflict injustice upon others, cannot expect fair treatment unto themselves."

Sacrifice: "None live alone, save they who will not share their fortune with those around them."

Honor: "It is the guilt, not the guillotine, that constitutes the shame."

Spirituality: "To forsake one's inner being is to abandon thy hopes for thyself and thy world."

Humility: "Pride is a vice, which Pride itself inclines one to find in others, and overlook in oneself."

Once all these messages have been received, the Codex voluntarily turns its pages and reveals this information:

"Beyond shames egress in the center of the underworld there is a place of darkness. Beyond this darkness lies the gate to the core of the world. When thou art ready thou must call forth VERAMOCOR to unlock the gate and venture past ethereal wards and stealers of souls. That which the world hath lost, dost awaits thy coming!."

Codex Message in Ultima VI
The following message is revealed by the Codex as a result of the quest ordained by the Shrine of Singularity:

"To return the Codex to the Vortex, place a convex lens exactly midway between the Codex and the Flame of Singularity, so that the light from the flame converges on the Codex. Place a concave lens between the Codex and the Flame of Infinity, so that its light diverges over the Codex. Then place the eight Moonstones within the Vortex Cube. Set it on the ground in front of the Codex, and use it to return the Codex from whence it came."

Other Prophecies
In the documentation that comes with Ultima VI, the following is revealed by Lord British as a prophecy given by the Codex:

"One will arise with the strength of an army, the vision of a prophet and the heart of a saint. This Great One will bring about an end to the struggle between the Darkness and the Light."

Trivia

 * The Codex can't be read in Ultima VII. This is probably because the Codex would ultimately tell the Avatar the reason for being on Britannia, which would make the game too easy.