Shooting an apple off one's child's head
Palnatoki
The earliest known occurrence of the motif is from the 12th century, in Saxo Grammaticus' version of the story of Palnatoki, whom he calls Toko (Gesta Danorum Book 10, chapter 7).
Palnatoki
Toko, who had been for some time in the service of the king [Harald Bluetooth], had, by the deeds in which he surpassed his fellow-soldiers, made several enemies of his virtues. One day, when he had drunk rather much, he boasted to those who were at table with him, that his skill in archery was such that he could hit, with the first shot of an arrow, ever so small an apple set on the top of a wand at a considerable distance. His detractors hearing these words, lost no time in conveying them to the ears of the king. But the wickedness of the prince speedily conveyed the confidence of the father to the peril of the son, ordering the sweetest pledge of his life to stand instead of the wand, from whom, if the utterer of the boast did not strike down the apple which was placed on him at the first shot of his arrow, he should with his own head pay the penalty of his idle boast. . . . When the youth was led forth, Toko carefully admonished him to receive the whiz of the coming arrow as steadily as possible, with attentive ears, and without moving his head, lest by a slight motion of his body he should frustrate the experience of his well-tried skill. He made him also, as a means of diminishing his apprehension, stand with his back to him, lest he should be terrified at the sight of the arrow. He then drew three arrows from his quiver, and the first he shot struck the proposed mark. Toko then being asked by the king why he had taken so many arrows out of his quiver, when he was to make but one trial with the bow, "That I might avenge on thee," said he, "the error of the first by the points of the others, lest my innocence might hap to be afflicted and thy injustice to go unpunished!"
Þiðrekssaga
In the 13th-century Þiðrekssaga, chapter 128, Egill, brother of Völund, is commanded by King Nidung to shoot an apple off his three-year-old son's head: