Etra traveled with her husband Falanto and the Parthenian army to found their only Spartan colony, present-day Taranto. Before leaving, Falanto consulted the Oracle of Delphi in search of a response about his own future. The oracle of Apollo, through the Pythia, thus ruled:

“I grant you to dwell Saturus and be the bane of the Iapigi.”

Falanto also asked for a sign by which to know when the appropriate time would come, and the oracle ruled:

“When you see it rain from the clear sky, you will conquer territory and cities.”

Having reached the lands of the Iapigi, there came a day when Falanto’s ambitions and disappointments saw him sitting on the ground with his head resting on the knees of his wife, who, tired and discouraged, began to weep and bathe him with her tears. But his wife’s name Etra (ancient Greek Αἴθρα) has precisely the meaning of “clear sky,” so Falanto understood that the oracle’s words were referring to his wife’s tears. He then set about to found his city starting from the very landing area, Saturo, a locality that still exists a few kilometers from Taranto, where there is an important archaeological zone.