Theseus was a demigod that was very strong and smart. He traveled the land defeating thieves and monsters.
One of these was the tree bender. The tree bender would tie his victims to bent down trees. He would let go of the trees and the victim would be torn apart.
He journeyed to Athens to meet the King who may have been his father. When he found his father, the city had to send away 14 tributes to fight the Minotaur. Theseus volunteered to go
He promised his father that if he survived the Minotaur he would sail back with white sails on his ship. Once he got to the Island of Crete, a princess fell in love with him. She gave him some string to navigate through the maze.
He defeated the Minotaur and exited the labyrinth. When he left Crete, the princess was let behind and they sailed back home.
When he returned home to Athens he forgot to change the sails to white. When his father saw black sails he thought Theseus was dead and jumped off a building into the sea. Theseus then became the King of Athens.