1,100,000 BCE

Unknown

 * Prior to 1,100,000 BCE, ancient humanity achieved its earliest known spacefaring technological state and settled on numerous worlds along the galactic margin. They would later experience several dark ages resulting in the loss of most of their historical records and knowledge before eventually encountering the Forerunners.
 * Around 1,100,000 BCE, the Forerunner Theoretical known as Boundless begins to study a particular star within the Path Kethona galaxy. When she continues her work in defiance of Warrior orders to the contrary, she is eventually prosecuted, her studies are suppressed, and she is forced to enter a Cryptum. A thousand years later, Boundless' Cryptum is opened and it is discovered that she has died inside due to a malfunction in the Cryptum, supposedly resulting from sabotage. Her former students discreetly dispose of her body. After Boundless' death, the entire Theoretical rate is absorbed into the Builders.