Grossmann established synod headquarters in Dubuque and quickly backed the work of establishing congregations for the newly arriving German immigrants to Iowa. He was instrumental in the founding of St. John's Lutheran in Dubuque. Another early enterprise was in Sherrill, Iowa, where he purchased of land with Bavarian immigrants Georg and Heinrich Vogel from Hof, Bavaria,Vogel, J. Heath. Journal of Heinrich Vogel. Houston: 2017: 153. in 1855 in order to establish a school and church. This became St. Matthew's Lutheran, where the original Wartburg Seminary bell sent by Löhe from Germany and first used in Saginaw has been housed since Easter 1869.
