Princess Katharina's younger sister, Princess Sophie of Isenburg, married Georg Friedrich, Prince of Prussia, in August 2011. This wedding, however, had to take place in Potsdam-Sanssouci as the bridegroom is the head of the former Imperial House of Germany and Royal House of Prussia. Katharina and Sophie's eldest brother Alexander, the heir to the family castle, was married to plastic surgeon Sarah Lorenz in a civil ceremony in Birstein, followed by a Catholic ceremony near her hometown of Munich in June 2014.