Orddu revealed that the brooch was a powerful enchanted item created in ancient times by Menwy the Bard; it enhanced the senses and awareness of its wearer, and imbued him or her with symbolic, prophetic dreams.
HistoryThe Council at Caer Dallben, through the brooch's power Adaon dreamt of his own death; evidently the outcome was not fixed, but rather hinged on Taran's choice whether to go to the Marshes of Morva or to Caer Cadarn. Adaon, though Companions, so he deferred the choice to Taran. The Assistant Pig-Keeper decided on Morva and unknowingly sealed Adaon's fate.
Adaon soon willed the brooch to Taran, reporting of it only that his betrothed had given it to him. (How she acquired the item remains unknown.) On his death Adaon bequeathed it to Taran. Later, in the Marshes, it proved to be the sole item which the three enchantresses would accept in exchange for the Black Crochan.