The Ancients were noted ancestors or peoples from a cultures distant past.
According to the Eymorg Kara, in 2268, as by command of the Ancients that the priestess leader was the only one permitted to learn from the Great Teacher. (TOS: "Spock's Brain")
When later attempting to learn the magic of the Megans in 2270, Spock drew a pentangle, stating, "I believe this is how the Ancients used to draw their mystic symbols." (TAS: "The Magicks of Megas-Tu")
For his last act as the sirah of an unidentified village on Bajor in 2369, the Sirah exclaim how the people of the village united against the Dal'Rok, which possessed "a hatred of the Ancients." (DS9: "The Storyteller")