 On Christmas Day, 1860 Gross married Catharina Christiana Stieff (1833–1906), Charles' daughter.His joining the Stieff family business was an excellent combination.The Stieff piano was considered one of the finest pianos made, superior even to the Steinway, because its piano action was made by Wessell, Nickel & Gross, "world-renowned and synonymous with the highest quality piano action that one could buy."