<P> In another version, King Minos had waged war with the Athenians and was successful . He then demanded that, at nine - year intervals, seven Athenian boys and seven Athenian girls were to be sent to Crete to be devoured by the Minotaur, a half - man, half - bull monster that lived in the Labyrinth created by Daedalus . </P> <P> On the third occasion, Theseus volunteered to slay the monster to stop this horror . He took the place of one of the youths and set off with a black sail, promising to his father, Aegeus, that if successful he would return with a white sail . Like the others, Theseus was stripped of his weapons when they sailed . On his arrival in Crete, Ariadne, King Minos' daughter, fell in love with Theseus and, on the advice of Daedalus, gave him a ball of thread (a clew), so he could find his way out of the Labyrinth . That night, Ariadne escorted Theseus to the Labyrinth, and Theseus promised that if he returned from the Labyrinth he would take Ariadne with him . As soon as Theseus entered the Labyrinth, he tied one end of the ball of string to the door post and brandished his sword which he had kept hidden from the guards inside his tunic . Theseus followed Daedalus' instructions given to Ariadne; go forwards, always down and never left or right . Theseus came to the heart of the Labyrinth and also upon the sleeping Minotaur . The beast awoke and a tremendous fight then occurred . Theseus overpowered the Minotaur with his strength and stabbed the beast in the throat with his sword (according to one scholium on Pindar's Fifth Nemean Ode, Theseus strangled it). </P> <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> <P> According to Plutarch's Life of Theseus, the ship Theseus used on his return from Crete to Athens was kept in the Athenian harbour as a memorial for several centuries . </P>

In what way is theseus responsible for the death of his father