At 16, Theseus lifted the rock under which his father Aegus had placed the the sword and sandals that would identify Theseus as his son, and travelled to Athens to reclaim his birthright.
On the way to Athens, Theseus killed six bandits, at the six entrances to the underworld. These bandits were the "clubber" Periphetes, the Crommyonian Sow, Sinis the bender of trees,
Sciron, Cercyon, and Procrustes.
After he arrived in Athens, he killed the Marathonian Bull. Then he went to Crete and killed the Minotaur, ending the annual tribute to King Minos.
After his return to Athens, he did many other famous deeds including killing drunken centaurs who attempted to kidnap women at a wedding feast, and defeating the Amazons and marrying their queen.