<P> After decapitating the beast , Theseus used the string to escape the Labyrinth and managed to escape with all of the young Athenians and Ariadne as well as her younger sister Phaedra . Then he and the rest of the crew fell asleep on the beach of the island of Naxos , where they stopped on their way back , looking for water . Athena woke Theseus and told him to leave early that morning and to leave Ariadne there for Dionysus , for Naxos was his island . Stricken with distress , Theseus forgot to put up the white sails instead of the black ones , so his father , the king , believing he was dead , committed suicide , throwing himself off a cliff of Sounio and into the sea , thus causing this body of water to be named Aegean Sea . Dionysus later saw Ariadne crying out for Theseus and took pity on her and married her . </P>
in what way is theseus responsible for the death of his father
forgot to put up the white sails instead of the black ones , so his father , the king , believing he was dead , committed suicide