The Heinrich Spaeth papers contain 82 items: 33 letters, 29 photographs, 13 pieces of ephemera, 3 legal documents, 3 newspaper clippings, and a diary. The materials span 1862 to 1949, with the bulk of items covering the period between 1910 and 1915.
The Correspondence and Documents series contains letters to and from Spaeth, spanning 1871-1918. Though written many years after the Civil War, most of these relate to the experiences of the 9th Ohio Volunteer Infantry, particularly at the Battle of Chickamauga. Several men who served in Van Derveer's Brigade wrote letters to Spaeth with accounts of the closing hours of the engagement. They attempted to refute the claims of Archibald Gracie, who wrote in his book The Truth about Chickamauga that the soldiers under General Ferdinand Van Derveer had been routed and driven off Snodgrass Hill on the evening of September 20, 1863. The soldiers from the 9th Ohio Infantry who provided these accounts were George A. Schneider (May 24, 1912), C.W.H. Luebbert (June 7, 1912), Ferdinand Zimmerer (June 17, 1912), Alvin Arand (June 18, 1912), and Herman Gerbhardt (June 20, 1912). Though written almost 50 years after the battle took place, the letters provide many details in support of their claims. Also included is an undated letter from Spaeth to Gracie, which contradicts Gracie's claims and states, "the third and last stand on Snodgrass Hill was as perfect as any man could or would ask." In the letter, Spaeth also discussed the official and revised casualty figures for the engagement.
Additional letters from the same period relate to controversy over Civil War monuments in Chattanooga, Tennessee, commemorating actions during the Battle of Missionary Ridge. On November 26, 1910, Colonel Judson W. Bishop of the 2nd Minnesota Volunteer Infantry wrote to Spaeth, complaining of efforts "persistently made during the past fifteen years by the Turchin's Brigade association to appropriate for [General John B.] Turchin" ground allegedly captured by Van Derveer's Brigade at Missionary Ridge on November 25, 1863. Bishop called the claims for Turchin "preposterous." Spaeth seconded the opinion in a letter to Captain Philip Rothenbush of the 35th Ohio Infantry, in which he called the actions "contemptble [sic]." An additional letter, dated July 5, 1915, also further addresses the issue of monuments in Chattanooga.
The Diary series contains Spaeth's diary, kept during his service with the 9th Ohio Infantry. The volume was written entirely in German Sütterlinschrift or old German blackletter handwriting; it describes his wartime experiences.
The Photographs series contains 29 graphic items, most of which are undated and unlabeled, spanning ca. 1860s-1949. The photographs are in a variety of formats and depict many members of the Spaeth family, including Heinrich Spaeth at various stages of life. One photograph shows a parade float advertising Spaeth's business with the sign, "Spaeth's Big Free China and Stove Show," and another shows Heinrich Spaeth in front of a home in Aurora, Indiana.
Ephemera series contains a roster for the 35th Ohio Volunteer Infantry (O.V.I.) Association and the Loyal Legion of the United States, newspaper clippings, German money, and a few miscellaneous items.