To celebrate the 70th birthday in 1898 of Dr. Friedrich Karl Castelhun (son-in-law of Paulus Roetter), a plaque was created which featured one of his most famous poems (a PDF print of the text and its English translation will accompany the purchase).  The original metal plaque went to Milwaukee and has since become lost (I tried to track it down, though let me know if you have any idea of its whereabouts), but the family retained a plaster version and this official print.