The sail of his ship is black not white, my son has died defeating the Minotaur, I cannot live without him...
No father you are mistaken! I am not dead, in my haste to escape from Crete I forgot to change the sails!
The Aegean Sea
However, as soon as the girl is out of sight, Theseus quickly sets sail again, leaving poor Ariadne, the very girl who helped him escape, stranded on a remote desert island. Angered by Theseus' ungrateful treatment of Ariadne, God planned a further horror in store for him.
In his haste to leave Ariadne, Theseus forgets to replace the black sail with the white sail so that his father would know from afar the outcome of his quest. His father, noticing the black sail instead of the white one, thinks Theseus is dead and throws himself off of a cliff in grief.
The sea where the great King fell was called the Aegean sea in his honour.