The lion and bull in combat is a common theme. It is considered a symbol of seasonal change, the lion, symbol of summer defeats the bull, winter, but there is debate about its real meaning. The lion's face is dark from centuries of touching, considered good luck.
Darius I was the greatest of the Achaemenid kings. He ruled from 522 to 486 BC. He is seen here (seated) in a relief sculpture, along with his successor, Xerxes. Darius is famous as a lawgiver, and many stories were told about his severity yet impartiality in administering the law. It appears that he strove to standardize legal practices all over his vast empire.