Garternay, said to mean Root of the Great Tree, was the old and possibly original home age of the people called the Ronay. Garternay was an ancient world that was orbiting a red giant sun, and it was known to the Ronay that their world would relatively soon no longer be able to sustain life. Fortunately they had developed the Art: a way to write special Books which provides a Link to another Age.
Several Ages were written to house the Ronay exiles, and the majority Linked to Terahnee, an immense fertile world. A conservative minority, led by the Writer Ri'neref, instead decided to leave the host of the Ronay, as they felt that the Ronay had become too arrogant and had forgotten their humility. This splinter fraction instead linked to the Age of D'ni (Earth), an Age written by Ri'neref. Here they formed the D'ni empire.
Garternay is believed to have been destroyed by natural forces at some point after the exodus, and, officially, no Linking Books have been found. However, Garternay was listed as an Age under preparation by the D'ni Restoration Council, suggesting at least one Linking Book had been found.