When Theseus was full fifteen years old, she took him up with her to the temple, and into the thickets which grew in the temple yard. She led him to a tall plane-tree, and there she sighed and said, "Theseus, my son, go into that thicket and you will find at the plane-tree foot a great flat stone. Lift it, and bring me what lies underneath."
Then Theseus pushed his way in through the thick bushes, and searching among their roots he found a great flat stone, all overgrown with ivy and moss.
He tried to lift it, but he could not. And he tried till the sweat ran down his brow from the heat, and the tears from his eyes for shame, but all was of no avail. And at last he came back to his mother and said, "I have found the stone, but I cannot lift it, nor do I think that any man could, in all the land."
Then she sighed and said, "The day may come when you will be a stronger man than lives in all the land." And she took him by the hand and went into the temple and prayed, and came down again with Theseus to her home.
And when a full year was past, she led Theseus up again to the temple and bade him lift the stone, but he could not.
Then she sighed again and said the same words again, and went down and came again next year. But Theseus could not lift the stone then, nor the year after.
He longed to ask his mother the meaning of that stone, and what might be underneath it, but her face was so sad that he had not the heart to ask.
So he said to himself, "The day shall surely come when I will lift that stone."
And in order to grow strong he spent all his days in wrestling and boxing, and hunting the boar and the bull and the deer among rocks, till upon all the mountains there was no hunter so swift as Theseus, and all the people said, "Surely the gods are with the lad!"
When his eighteenth year was past, Aithra led him up again to the temple and said, "Theseus, lift the stone this day, or never know who you are."