Theseus was Athens's great hero. While having all the qualities of a traditional hero, such as strength and courage, he was also intelligent and wise. His early adventures benefited the city and region. He was a successful king. He consolidated Athens's position in the region through shrewd political maneuvering. He led Athens's army on victorious campaigns. He is credited as the founder of Athens's democracy voluntarily turning many of his powers as king over to an elected assembly. He gained a reputation for helping the poor and oppressed.
His shedding of power also made it easier for him to continue going on adventures after he was king. "Not without Theseus" became a popular Athenian saying, reflecting the belief he should be included in any important undertaking.
While growing up he wanted to be like his older cousin Heracles. Perhaps the only example of conscious emulation by one Greek Hero of another. He became a fast friend of Heracles and they saved each others lives. Heracles through his strength. Theseus through his wisdom.
In middle age his wisdom deserted him. He began going on foolish adventures. He started making bad decisions. His efforts to produce an heir for the throne led to more problems. The people of Athens's grew tired on the turmoil he produced. Ultimately, he died in exile from Athens's. The city did not bother to bring his body home.
Generations pasted without much thought being given to Theseus. Then during the Persian wars Athenian solders reported seeing the ghost of Theseus and came to believe him responsible for their victories. The Athenian general Cimon received a command from the Oracle at Delphi to find Theseus's bones and return them to Athens. This he did and he was reburied in a magnificent tomb that also served as a sanctuary for the defenseless.