The Jataka, Vol. III, tr. by H.T. Francis and R.A. Neil, , at sacred-texts.com
"People cry "Where is she gone," etc.—This story the Master, whilst residing in the Bamboo Grove, told about Ajātasattu. The incident that led to the story has been already fully told in the Thusa Birth. 1 Here too the Master observed the king at the same moment playing with his boy and also listening to the Law. And knowing as he did that danger to the king will arise through his son, he said, "Sire, kings of old suspected what was open to suspicion, and kept their heirs in confinement, saying, "Let them bear rule, after our bodies have been burned on the funeral pyre." And with this he told a story of the past.
Once upon a time in the reign of Brahmadatta, king of Benares, the Bodhisatta was born in a brahmin family, and became a world-famed teacher. The son of the king of Benares, prince Yava, by name, after applying himself diligently to acquire all the liberal arts from him, being now anxious to depart, bade him good-bye. The teacher, knowing by his power of divination that danger would befall the prince through his son, considered how he might remove this danger from him, and began to look about him for an apt illustration.
 Now he had at this time a horse, and a sore place appeared on its foot. And in order to give proper attention to the sore the horse was kept to the stable. Now close by was a well. And a mouse used to venture out of its hole and nibble the sore place on the horse's foot. The horse could not stop it, and one day being unable to bear the pain, when the mouse came to bite him, he struck it dead with his hoof and kicked it into the well. The grooms not seeing the mouse said, "On other days the mouse came and bit the sore place, but now it is not to be seen. What has become of it?" The Bodhisatta witnessed the whole thing and said, "Others from not knowing ask, "Where is the mouse?"' But I alone know that the mouse has been killed by the horse, and dropped into the well." And making this very fact an illustration, he composed the first stanza and gave it to the young prince.
Looking about for another illustration, he saw that same horse, when the boil was healed, go out and make his way to a barley field to get some barley to eat, and thrust his head through a hole in the fence, and taking this as an illustration he composed a second stanza and gave it to the
prince. But the third stanza he composed by his own mother-wit and gave this also to him. And be said, "My friend, when you are established in the kingdom, as you go in the evening to the bathing tank, walk as far as the front of the staircase, repeating the first stanza, and as you enter the palace in which you dwell, walk to the foot of the stairs, repeating the second stanza, and as you go thence to the top of the stairs, repeat the third stanza." And with these words he dismissed him.
The young prince returned home and acted as viceroy, and on his father's death he became king. An only son was born to him, and when he was sixteen years old he was eager to be king. And being minded to kill his father, he said to his retainers, "My father is still young. When I come to look upon his funeral pyre I shall be a worn-out old man. What good will it be for me to come to the throne then?" "My lord," they said, "it is out of the question for you to go to the frontier and play the rebel. You must find some way or other to slay your father, and to seize upon his kingdom."  He readily agreed, and went in the evening, and took his sword and stood in the king's palace near the bathing tank, prepared to kill his father. The king in the evening sent a female slave called Mūsikā, saying, "Go and cleanse the surface of the tank. I shall take a bath." She went there and while she was cleaning the bath she caught sight of the prince. Fearing that what he was about might be revealed, he cut her in two with his sword and threw the body into the tank. The king came to bathe. Everybody said, "To-day the slave Mūsikā does not return. Where and whither is she gone?" The king went to the edge of the tank, repeating the first stanza:
Mūsikā, where hast thou fled?"
This is known to me alone:
In the well she lieth dead.
Thought the prince, "My father has found out what I have done." And being panic-stricken he fled and told everything to his attendants. After the lapse of seven or eight days, they again addressed him and said, "My lord, if the king knew he would not be silent. What he said must have been a mere guess. Put him to death." So one day he stood sword in hand at the foot of the stairs, and when the king came he was looking about for an opportunity to strike him. The king came repeating the second stanza:
 Thought the prince, "My father has seen me," and fled in terror. But at the end of a fortnight he thought, "I will kill the king by a blow from a shovel." So he took a spoon-shaped instrument with a long handle and stood poising it. The king climbed to the top of the stair, repeating the third stanza:
Like a baby with its toy,
Grasping this long spoon-like tool,
I will slay thee, wretched boy.
That day being unable to escape, he grovelled at the king's feet and said, "Sire, spare my life." The king after rating him had him bound in chains and cast into prison. And sitting on a magnificent royal seat shaded by a white parasol, he said, "Our teacher, a far-famed brahmin foresaw this danger to us, and gave us these three stanzas." And being highly delighted, in the intensity of his joy he gave forth the rest of the verses:
Nor by some act of filial piety.
Nay when my life was sought by this my son,
Escape from death through power of verse was won.
Knowledge of every kind he apt to learn,
And what it all may signify discern:
Though thou shouldst use it not, the time will be
When what thou hearest may advantage thee.
 By and bye on the death of the king the young prince was established on the throne.
The Master here brought his lesson to a close, and identified the Birth: "At that time the far-famed teacher was myself."
142:1 No. 338 supra.
143:1 Mūsikā means mouse, Yava barley.