Precursor

The precursors (also referred to as priors) are a semi-mythological antecedent civilisation referenced in a handful of Forerunner texts. A pair of references within the aforementioned texts suggest that the precursors were viewed in a somewhat venerable light by the Forerunners, who believed the Precursors to have served as guiding figures to Forerunner civilisation in its earlier stages. The Forerunners appear to have believed that they could have one day "followed in [the precursors'] footsteps", though the specifics of what this would have entailed remain elusive.

Whether the precursors existed at all is something subject to much debate, as to date no physical proof of their existence has been uncovered, nor have further references to the precursors been suggested outside of the original two texts. However, the preeminent accepted theories place the precursors as those who moved original Forerunner populations away from Earth hundreds of millions of years ago, and may have guided these populations into technological enlightenment, alongside being responsible for many of the older ancient examples of biodisplacement encountered across the reaches of space.

While these theories have been commonly accepted by the scientific community, they remain largely that, as any solid details on the precursors are scattered and confused. Some references within the Forerunner archives contradict one another, indicating that belief in the precursors within Forerunner civilisation was not a universally-accepted practice - and that different groups within the Ecumene held opposing beliefs as to the origins of their own civilisation. Indeed, it is unknown as to whether the precursors constituted simply one species or multiple.