Antique Royal Bonn Hand Painted Porcelain Vase. Gilt painted three leaf clovers throughout. Brightly painted floral design. Measures - 13 1/4" high x 4 3/4" diameter. German porcelain. Royal Bonn is the nineteenth-and twentieth-century trade name used by Franz Anton Mehlem, who had a pottery in Bonn, Germany, from 1836 to 1931. Porcelain and earthenware were made. Royal Bonn used a monogram-and-tower mark that appeared on exported pottery only with Germany added. The factory was purchased by Villeroy & Boch in 1921 and closed in 1931. Many marks were used, most including the name Bonn, the initials FM, and a crown.