When the Czech lands were ruled by prince Křesomysl, a farmer named Horymír lived in the village of Neumětely. He had a white horse of extraordinary intelligence called Šemík. Due to Křesomysl's obsession to find treasures that were said to be hidden underground, people were encouraged to abandon farming and to become miners. Horymír was unhappy with Křesomysl's rule and warned that neglecting farming would result in famine. His protests were not liked by the miners who one day set Horymír's property on fire. Horymír and his followers in turn burned down the miners' village. Horymír was punished and sentenced for execution. When he was asked his last wish, he requested one last ride around the castle grounds on his beloved horse Šemík. His wish was granted. When Horymír got on his white horse, he whispered something in his ear. Šemík ran to the ramparts, jumped over them and slid down the cliff. When the on-lookers got to the ramparts, they were astonished to see Horymír and Šemík on the other side of the Vltava, galloping towards Neumětely.
The miraculous jump exhausted Šemík. The dying horse spoke to Horymír in a human voice and asked for a tomb to be built for him. Horymír did as the horse wished. The tomb has since disappeared but Šemík is said to be sleeping in the Vyšehrad rock, ready to come out when his help is needed again.