The Jataka, Vol. II, tr. by W.H.D. Rouse, , at sacred-texts.com
"There grows a tree," etc.--This story the Master told in Jetavana, about the Elder Sāriputta giving mango juice to the Sister Bimbādevī. When the Supreme Buddha inaugurated the universal reign of religion, whilst living in a room at Vesāli, the chief wife of the Gotama with five hundred of the Sākiya clan asked for initiation, and received initiation and full orders. Afterwards the five
hundred Sisters became saints on hearing the preaching of Nandaka. But when the Master was living near Sāvatthi, the mother of Rāhula thought to herself, "My husband on embracing the religious life has become omniscient; my son too has become a religious, and lives with hire. What am I to do in the midst of the house? I will enter on this life, and go to Sāvatthi, and I will live looking upon the Supreme Buddha and my son continually." So she betook herself to a nunnery, and entered the order, and went and lived in a cell at Sāvatthi, in company of her teachers and preceptors, beholding the Master and her beloved son. The novice Rāhula came and saw his mother.
One day, the Sister was afflicted with flatulence;  and when her son came to see her, she could not get to see him, but some others came and told him she was ill. Then he went in, and asked his mother, "What ought you to take?" "Son," said she, "at home this pain used to be cured by mango juice flavoured with sugar; but now we live by begging, and where can we get it?" Said the novice, "I'll get it for you," and departed. Now the preceptor of his reverence Rāhula was the Captain of the Faith, his teacher was the great Moggallāna, his uncle was the Elder Ānanda, and his father was the Supreme Buddha: thus he had great luck. However, he went to no other save only to his preceptor; and after greeting him, stood before him with a sad look. "Why do you seem sad, Rāhula?" asked the Elder. "Sir," he replied, "my mother is ill with flatulence." "What must she take?" "Mango juice and sugar does her good." "All right, I'll get some; don't trouble about it." So next day he took the lad to Sāvatthi, and seating him in a waiting-room, went up to the palace. The king of Kosala bade the Elder be seated. At that very moment the gardener brought a basket of sweet mangoes ripe for food. The king removed the skin, sprinkled sugar, crushed them up himself, and filled the Elder's bowl for him. The Elder returned to the place of waiting and gave them to the novice, bidding him give them to his mother; and so he did. No sooner had the Sister eaten, than her pain was cured. The king also sent messengers, saying, "The Elder did not sit here to eat the mango juice. Go and find out whether he gave it to any one." The messenger went along with the elder, and found out, and then returned to tell the king. Thought the king: "If the Master should return to a worldly life, he would be an universal monarch; the novice Rāhula would be his treasure the Crown Prince 1, the holy Sister would be his treasure the Empress, and all the universe would belong to them. I must go and attend upon them. Now they are living close by there is no time to be lost." So from that day he continually gave mango syrup to the Sister.
It became known among the Brothers how the Elder gave mango syrup to the holy Sister.  And one day they fell a-talking in the Hall of Truth: "Friend, I hear that the Elder Sāriputta comforted Sister Bimbādevī with mango syrup." The Master came in and asked, "What are you talking about now?" When they told him--"This is not the first time, Brothers, that Rāhula's mother was comforted with mango syrup by the Elder; the same happened before;" and he told them an old-world tale.
Once upon a time, when Brahmadatta was reigning in Benares, the Bodhisatta was born in a brahmin family living in a village of Kāsi. When he grew up, he was educated at Takkasilā, settled down into family life, and on the death of his parents embraced the religious life. After that he remained in the region of Himalaya, cultivating the Faculties and the Attainments. A body of sages gathered round him, and he became their teacher.
At the end of a long time he came down from the hills to get salt and seasoning, and in the course of his wanderings arrived at Benares, where he took up his abode in a park. And at the glory of the virtue of this company of holy men the palace of Sakka shook. Sakka reflected, and perceived what it was. Thought he, "I will do an injury to their dwelling; then their stay will he disturbed; they will be too much distressed to have tranquillity of mind. Then I shall be comfortable again." As he bethought him how to do it, he hit upon a plan. "I will enter the chamber of the chief queen, just at the middle watch of the night, and hovering in the air, I will say--'Lady, if you eat a midmost mango 1, you will conceive a son 2, who shall become a universal monarch.' She will tell the king, and he will send to the orchard for a mango fruit: I will cause all the fruit to disappear. They will tell the king that there is none, and when he asks who eats it, they will say 'The ascetics'." So just in the middle watch, he appeared in the queen's chamber, and hovering in the air, revealed his godhead, and conversing with her, repeated the first two stanzas:--
"Lady, you are a mighty Queen indeed;
The King, your husband, holds you lief and dear.
Bid him procure the mango for your need,
And he the Midmost fruit will bring you here."
These stanzas did Sakka recite to the queen; and then bidding her be careful, and make no delay, but tell the matter to the king herself, he encouraged her, and went back to his own place.
Next day, the queen lay down, as though ill, giving instructions to her maidens. The king sat upon his throne, under the white umbrella, and looked on at the dancing. Not seeing his queen, he asked a handmaid where she was.
"The queen is sick," replied the girl.
So the king went to see her; and sitting by her side, stroked her back, and asked, "What is the matter, lady?"
"Nothing," said she, "but that I have a craving for something."
"What is it you want, lady?" he asked again.
"A middle mango, my lord."
"Where is there such a thing as a middle mango?"
"I don't know what a middle mango is; but I know that I shall die if I don't get one."
"All right, we will get you one; don't trouble about it."
So the king consoled her, and went away. He took his seat upon the royal divan, and sent for his courtiers.  "My queen has a great craving for a middle mango. What is to be done?" said he.
Some one told him, "A middle mango is one which grows between two others. Send to your park, and find a mango growing between two others; pluck its fruit and let us give it to the queen." So the king sent men to do after this manner.
But Sakka by his power made all the fruit disappear, as though it had been eaten. The men who came for the mangoes searched the whole park through, and not a mango could they find; so back they went to the king, and told him that mangoes there were none.
"Who is it eats the mangoes?" asked the king.
"The ascetics, my lord."
"Give the ascetics a drubbing, and bundle them out of the park!" he commanded. The people heard and obeyed: Sakka's wish was fulfilled. The queen lay on and on, longing for the mango.
The king could not think what to do. He gathered his courtiers and his brahmins, and asked them, "Do you know what a middle mango is?"
Said the brahmins: "My lord, a middle mango is the portion of the gods. It grows in Himalaya, in the Golden Cave. So we have heard by immemorial tradition."
"Well, who can go and get it?"
"A human being cannot go; we must send a young parrot."
At that time there was a fine young parrot in the king's family, as big as the nave of the wheel in the princes' carriage, strong, clever, and full of sharp devices. This parrot the king sent for, and thus addressed him,
"Dear parrot, I have done a great deal for you: you live in a golden cage; you have sweet grain to eat on a golden dish; you have sugared water to drink. There's something I want you to do for me,"
"Speak on, my lord," said the parrot.
"Son, my queen has a craving for a middle mango; this mango grows in Himalaya, in the Golden Mountain; it is the gods' portion,  no human being can go thither. You must bring the fruit back from thence."
"Very good, my king, I will," said the parrot. Then the king gave him sweetened grain to eat, on a golden plate, and sugar-water to drink; and anointed him beneath the wings with oil an hundred times refined; then he took him in both hands, and standing at a window, let him fly away.
The parrot, on the king's errand, flew along in the air, beyond the ways of men, till he came to some parrots which dwelt in the first hill-region of Himalaya. "Where is the middle mango?" he asked them; "tell me the place."
"We know not," said they, "but the parrots in the second range of hills will know."
The parrot listened, and flew away to the second range. After that he went on to the third, fourth, fifth, and sixth. There too the parrots said, "We do not know, but those in the seventh range will know." So he went on there, and asked where the middle mango tree grew.
"In such and such a place, on the Golden Hill," they said.
"I have come for the fruit of it," said he, "guide me thither, and procure the fruit for me."
"That is the portion of the king Vessavaṇa. It is impossible to get near it. The whole tree from the roots upwards is encircled with seven iron nets; it is guarded by thousands of millions of Kumbhaṇḍa goblins; if they see any one, he's done for. The place is like the fire of the dissolution and the fire of hell. Do not ask such a thing!"
"If you will not go with me, then describe the place to me," said he.
So they told him to go by such and such a way. He listened carefully to their instructions. He did not show himself by day; but at dead of night, when the goblins were asleep, he approached the tree, and began softly to climb on one of its roots, when clink! went the iron net --the goblins awoke--saw the parrot, and seized him, crying, "Thief!" Then they discussed what was to be done with him.
Says one, "I'll throw him into my mouth, and swallow him!"
Says another, "I'll crush him and knead him in my hands and scatter him in bits!"
Says a third, "I'll split him in two, and cook him on the coals and eat him!"
The parrot heard them deliberating. Without any fear he addressed them, "I say, Goblins, whose men are you?"
"We belong to king Vessavaṇa."
"Well, you have one king for your master, and I have another for mine. The king of Benares sent me here to fetch a fruit of the middle mango tree. Then and there I gave my life to my king, and here I am. He who loses his life for parents or master is born at once in heaven. Therefore I shall pass at once from this animal form to the world of the gods!" and he repeated the third stanza:
After this fashion did he discourse, repeating this stanza. The goblins listened, and were pleased in their heart. "This is a righteous creature," said they, "we must not kill him--let him go!" So they let him go, and said, "I say, Parrot, you're free! Go unharmed out of our hands!" 
"Do not let me return empty-handed," said the parrot: "give me a fruit off the tree!"
"Parrot," they said, "it is not our business to give you fruit off this tree. All the fruit on this tree is marked. If there is one fruit wrong we shall lose our lives. If Vessavaṇa is angry and looks but once, a thousand goblins are broken up and scattered like parched peas hopping about on a hot plate. So we cannot give you any. But we will tell you a place where you can get some."
"I care not who gives it," said the parrot, "but the fruit I must have. Tell me where I may get it."
"In one of the tortuous paths of the Golden Mountain lives an ascetic, by name Jotirasa, who watches the sacred fire in a leaf-thatched hut, called Kañcana-patti or Goldleaf, a favourite of Vessavaṇa; and Vessavaṇa sends him constantly four fruits from the tree; go to him."
The parrot took his leave, and came to the ascetic; he gave him greeting, and sat down on one side. The ascetic asked him,
"Where have you come from?" "From the king of Benares." "Why are you come?"
"Master, our Queen has a great craving for the fruit of the middle mango, and that is why I am come. Howbeit the goblins would not give me any themselves, but sent me to you."
"Sit down, then, and you shall have one," said the ascetic. Then came the four which Vessavaṇa used to send. The ascetic ate two of them, gave the parrot one to eat, and when this was eaten he hung the fourth by a string, and made it fast around the parrot's neck, and let him go--"Off with you, now!" said he. The parrot flew back and gave it to the Queen. She ate it, and satisfied her craving, but still all the same she had no son.
 When the Master had ended this discourse, he identified the Birth in these words: "At that time Rāhula's mother was the Queen, Ānanda was the parrot, Sāriputta was the ascetic who gave the mango fruit, but the ascetic who lived in the park was I myself."
268:1 Two of the seven ratanas, or Treasures of the Empire of an universal monarch.
269:1 The phrase is meant to be enigmatical. It is explained below.
269:2 The idea of conception by eating of fruit and in other abnormal ways is fully discussed in The Legend of Perseus, E. S. Hartland, vol. i. chaps. 4-6.