What's the story depicted in this painting?
 

Hans Zatzka "Die Vision des heiligen Hubertus"

Miracle of St.. Hubert.
St. Hubert Catholic saint, the patron of hunters in the Western tradition. One day while hunting he saw a miraculous deer with a gold cross between the horns and, inspired by this sign, became a model Christian and gave away all his possessions to the poor.
  There is even a German hunting liquor or balm with this deer on the label. Everywhere is sold, do not remember the name.
St. HUBERT (~ 655 - 727), missionary and bishop of Liege. According to legend, he turned to Christianity after he was a deer with a shining cross between its horns. Later St. Hubert recognized patron saint of hunters.