Galveston Daily News, August 23, 1895; Muster Rolls, Company B, Fifth Texas Infantry, Archives of the Nesbitt Memorial Library, Columbus; Pauline A. Pinckney, Painting in Texas (Austin: University of Texas Press, 1967), pp. 141-145; Colorado County District Court Records, Civil Cause File No. 1790: H. A. Tatum v. Jane Tatum, Minute Book C2, p. 575. No primary sources, other than his paintings, have been located for Hoppe. Despite diligent searching, no record of his birth, his arrival in the United States, his presence in Texas or any other state, or of his death, has been located. All of his pictures, three of which remained in the hands of Leyendecker's descendants until 1976, are now a part of the collection of the San Antonio Museum of Art. For the best discussion of his work, and photographs of his four known pictures, see Cecilia Steinfeldt, Art for History's Sake: The Texas Collection of the Witte Museum (Austin: Texas State Historical Association, 1993), pp. 131-134.