What is the "True Cross" from the novel, The Iron King?

The True Cross is one of the greatest treasures belonging to the Knight's Templars. It is thought to be huge golden cross with a tiny piece of the 'real' cross of the Crucifixion of Jesus Christ. The Treasury of France confiscates the True Cross when the Knight's are persecuted and is later given to a monastery as the last dying wish of King Philip the Fair.