Earlier Empires

In Poul Anderson's History of Technic Civilization, Ythrians and Merseians get the hyperdrive from Terrans who invented it independently. However, it is known that there was a previous star traveling race and we learn that they were the telepathic Chereonites. How many such earlier races are there in sf? No doubt many. I think that there was a previous civilization in Ursula K Le Guin's future history although that is one that I have neither read recently nor reread.

We will refer to one other work by Anderson, four by Blish and one by Niven. In Anderson's After Doomsday, the FTL drive spreads like dandelion seeds among many intelligent species. It is not known whether it was discovered once or many times or by whom.

In James Blish's Cities In Flight, there have been four great civilizations in the Milky Way:

I ?;
II the Vegan Tyranny;
III the Earthman culture;
IV the Web of Hercules.

In Blish's Jack Loftus novels, the Heart Stars empire is much older than humanity and the energy beings called "Angels" knew several previous interstellar civilizations in other galaxies. (Blish, like Anderson, goes intergalactic a few times.) In Blish's "This Earth of Hours," the Terrestrial Matriarchy comes into conflict with an ancient telepathic Central Empire whereas, in his "A Style In Treason," High Earth's adversary, the Green Exarch, draws tithes from six fallen empires older than man.

In Larry Niven's Known Space History, the now extinct Thrintun ruled the galaxy three billion years ago and, like the Chereionites, left a telepathic legacy.