The Dawn Ages
"The Dawn Ages" is the term used by modern Matoran scholars to describe the earliest days of the universe, now largely remembered as myth, in which the founding principles of the Matoran Universe were established.
History
Fearing the destruction of the planet of Spherus Magna, the Great Beings created the Great Spirit Robot as a machine capable of mending their planet. However, due to geological reasons, they knew that the planet could not be reformed for several thousand years, and so they sent the Great Spirit Robot, commanded by an AI known as Mata Nui, on a mission of space exploration in the meantime.
The Great Spirit Robot, being the size of continents, needed a vast amount of labor to keep itself running. This was accomplished by the placement of Oropi, or biomechanical beings, within the robot, who would perform unique functions to assist in its maintenance and repair.