Eraavis was a planet in the Pegasus galaxy. Angelus thought Eraavis was his homeworld and thought he was a Ancient who had been monitoring an experiment to use nanite to improve the intellect of a planet's population, just to remain in stasis for several centuries after an unexpected culling interfered experiment.
The reality was very different: in fact, the planet wasn't inhabited, and Angelus never set a foot there. When the Apollo visited the world uncovered than the Asurans bombarded the planet from the orbit, leaving it into a charred ball, blackened and cratered, without barely atmosphere and radioactive. In reality, the Replicators simply had used the planet as target to test planetary bombardment techniques. (SGA: "Angelus")