What is "riegelhaube"

The Riegelhaube is a head covering made with complex and precious materials and worn by women of the affluent class. It was worn mainly in the 18th and 19th centuries in and around Munich. In the Gallery of Beauties of King Ludwig I of Bavaria is the portrait of Helene Sedlmayr, epitome of the "beautiful Municher," and is shown wearing a Riegelhaube.