The expression "raining cats and dogs" has been traced back to the Dark Ages, when many superstitious people believed that animals such as cats and dogs had magical powers. The cat was thought by sailors to have a lot to do with storms; witches that were believed to ride in the storms were often pictured as black cats. Dogs (and wolves) were symbols of winds. The Norse storm god Odin was frequently shown surrounded by dogs and wolves. When a thunderstorm occurred, people would say it was raining cats and dogs, with the cats symbolizing the rain and the dogs representing the storm winds.