The Twin Prophecies were made by Caymus, an Aldar who has been titled the greatest prophet of all time. The prophecies suggested that Maya would bear twins with powers rivalling those of the Aldar and that Proteus would be overthrown as leader of the Gods.
The first prophecy was fulfilled, in part, when Maya did indeed give birth to two children, the products of both Order and Chaos. They came to be known as humans and were named Sinope and Callisto.
The prophecy regarding Proteus being overthrown was only partly true. Centuries later, after the Chaos Wars, Ayar and Proteus re-merged to become Sarapis, the Logos.