Gypsy Folk Tales, by Francis Hindes Groome, [1899], at sacred-texts.com
A lord, his wife, and his daughter live at a great castle. A poor lad is engaged to mind the sheep. The daughter gives him bread and beer in a basket for lunch. The old lord explains that previous servants have always come back with one cow short. In the field a little man comes to Jack. Jack gives him as much as he can eat; and the little man gives Jack a plum. The little man explains that a giant in a neighbouring castle steals a cow daily. He gives Jack a pennyworth of pins, and bids him put them in the giant's drink. Jack goes to the giant, and asks for work. The giant goes to get drinks, and Jack mixes up the pins in the giant's glass. The giant drinks, falls ill, and dies. Jack tells the little man how he has fared, and returns with the full tale of cows. The master is surprised. Presently his daughter comes in. She tells Jack that to-morrow she is to be killed by a dragon, and would like him to be there to see. Jack refuses, but gives the girl a plum, which she eats.
[paragraph continues] Next morning she gives him his food, and off he goes. He shares it as before with the little man, who bids him take a key, unlock a large door, and take out a black horse and black clothes, with a sword he will find there. Then, having watered his horse, he is to go and fight the dragon. He goes, and knocks the dragon about with his sword. The dragon shoots fire from his mouth, but the horse throws up the water he has drunk, and quenches it. Jack puts back the horse, changes his clothes, and goes home with the cows. He gives another plum to the girl, who has to meet the dragon again next day, and asks Jack to be there. He refuses. Next morning she gives Jack his food, and Jack at the little man's suggestion asks for more. He gets it, goes, and shares it with the little man. It is the same as before, only this time he gets a white horse and white clothes. The little man tells Jack that to-morrow is the last day of the fight, and bids him rise early, and ask the young lady to send more food. Jack gives her another plum. This time she prepares the food over-night, as she has to meet the dragon at daybreak. She wants Jack to come and see, but he refuses--'must see after the cows.' He gets a red horse and red clothes this time, and the horse drinks the water dry. The fire from the dragon burns the lady's hair, but the horse's flood of water quenches it; and between them they kill the dragon. The lady cuts off a lock of Jack's hair with a golden scissors. He returns to the castle, and there the girl tells him about the fight and gets another plum. Then there is the usual dinner. Every guest has to lay his head in the lady's lap to let her see whether the lock matches, Jack having meanwhile gone off as usual with his cows, and shared his food with the little man. They fail to match the hair, so they bring up the servants--Jack last of all, wearing the red clothes underneath his own rags. He marries the young lady, and they live first in the dead giant's castle, and then, the parents having died, in her father's.
No exact parallel, but the story reminds one inter alia of the sheep-grazing episode in 'Mare's Son' (No. 20), and of the Polish-Gypsy 'Tale of a Foolish Brother and of a Wonderful Bush' (No. 45).