Every ninth year this offering was to be despatched. The more common story was, that the youths and maidens thus destined to destruction were selected by lot—but the logographer Hellanikus said that Minôs came to Athens and chose them himself.[528] The third period for despatching the victims had arrived, and Athens was plunged in the deepest affliction, when Thêseus determined to devote himself as one of them, and either to terminate the sanguinary tribute or to perish. He prayed to Poseidôn for help, and the Delphian god assured him that Aphroditê would sustain and extricate him. On arriving at Knossus he was fortunate enough to captivate the affections of Ariadnê, the daughter of Minôs, who supplied him with a sword and a clue of thread. With the former he contrived to kill the Minôtaur, the latter served to guide his footsteps in escaping from the labyrinth. Having accomplished this triumph, he left Krête with his ship and companions unhurt, carrying off Ariadnê, whom however he soon abandoned on the island of Naxos. On his way home to Athens, he stopped at Dêlos, where he offered a grateful sacrifice to Apollo for his escape, and danced along with the young men and maidens whom he had rescued from the Minôtaur, a dance called the Geranus, imitated from the twists and convolutions of the Krêtan labyrinth. It had been concerted with his father Ægeus, that if he succeeded in his enterprise against the Minôtaur, he should on his return hoist white sails in his ship in place of the black canvas which she habitually carried when employed on this mournful embassy. But Thêseus forgot to make the change of sails; so that Ægeus, seeing the ship return with her equipment of mourning unaltered, was impressed with the sorrowful conviction that his son had perished, and cast himself into the sea. The ship which made this voyage was preserved by the Athenians with careful solicitude, being constantly repaired with new timbers, down to the time of the Phalerian Dêmêtrius: every year she was sent from Athens to Dêlos with a solemn sacrifice and specially-nominated envoys. The priest of Apollo decked her stern with garlands before she quitted the port, and during the time which elapsed until her return, the city was understood to abstain from all acts carrying with them public impurity, so that it was unlawful to put to death any person even under formal sentence by the dikastery. This accidental circumstance becomes especially memorable, from its having postponed for thirty days the death of the lamented Socratês.[529]