Call them the Firstborn. Though they were not remotely human, they were flesh and blood, and when they looked out across the deepness of space, they felt awe, and wonder - and loneliness. As soon as they possessed the power, they began to seek fellowship among the stars.

It was the Pleistocene when the great spaceship had reached the Earth. In a geostationary orbit above a point on the equator, its occupants had released a multitude of remote-controlled probes to study the different biomes. The luscious forests, the vast deserts, the deep oceans, the vast expanses of ice at the poles, even the atmosphere that stood above them all. Somewhere, a species that could be manipulated toward intelligence was bound to exist.

The search came to an end in a region of eastern Africa that, millions of years later, would be known as the Olduvai Gorge.
Although Clindar had never left his exploration shuttlecraft, he had sent an emissary: an instrument of teaching, in the shape of a translucent monolith, that would attract the attention of the resident tribe of australopitheci and interface with their brains, to provide them with the necessary connections that would kickstart the virtuous cycle of the creation of intelligence.
His mission, however, was not over yet. He piloted his shuttlecraft over a crater in the southern hemisphere on the moon, and, with skillfully controlled traction fields, he exposed the solid rock under the regolith. There, he buried another tool: a signalling device, emitting a strong magnetic field, programmed to transmit a signal to report when it would be disinterred.

Wondering whether those curious mammals would ever evolve enough to find it, Clindar maneuvered his shuttlecraft into the mothership, which then set a course toward the Stargate. He would never visit that star system again.