Theseus is an ancient Greek hero, son of Aegeus, the king of Athens, and Aethra, daughter of Pittheus, the king of Troezen. Just before he left Troezen, Aegeus had hidden his sword and a pair of sandals underneath a great rock, and asked Aethra to reveal this secret to his son when he was strong enough to move the rock. His childhood Theseus spent with his mother, who did not say him who his father was until he grew up. Then wearing the sandals and armed with the sword, Theseus set off in search of his father.
See: Nicolas Poussin Theseus Finding His Father's Arms.
The legend of Theseus is very rich, and we'll add new episodes when we publish other paintings, devoted to him.