The collection consists of letters, military memos, invoices of loans, civil and religious registries of families who later joined the Mucker religious-therapeutic community. Among the earliest letters are those sent by German protestant families in the 1850s to their kin who immigrated to southern Brazil (later deemed by neighbors as "false saints" Mucker). These letters detail quotidian life on both sides of the Atlantic.

Schnell family letters, mainly authored by Carlos Jacob Schnell, a German-Brazilian soldier fighting in the war against Paraguay (1864-1868), make up the majority of correspondence. Schnell writes in the German-Brazilian dialect, Hunsrückisch, to his parents, who later joined the meetings around the trances of Jacobina Mentz Maurer and the herbal treatments of her husband, the healer João Jorge Maurer. The letters detail personal travails and military campaigns (a rarity as most of the Brazilian soldiers were illiterate at the time).

Other documents consist of letters from the Sehn family and letters drafted by the Mucker leadership, including a lengthy report on the movement by João Jorge Klein in Hunsrückisch and in Portuguese. There exists a one-of-a-kind hand-written hymnal, containing the favorite hymns sung by the Mucker in their religious meetings. Military reports and memos detail the attack against the community, known as the Mucker War. On July 19, 1874, provincial and imperial troops, supported by locals, attacked the Maurers' house and set it on fire. Dozens of Mucker followers died in the attack. Jacobina escaped with her newborn child and hid in the nearby woods with remaining devotees. Two weeks later, local colonists and soldiers found and killed the group.

Also included is a bound manuscript (circa 1850s-1870s) titled Vom Katechismus consisting of 274 pages written in Gothic German and in a local Hunsrükisch German dialect spoken in southern Brazil. It contains theological and everyday reflections of the German-born Georg Klein, who immigrated to southern Brazil in 1853, and was later imprisoned in the early 1870s as a supposed leader of the Mucker "false saints" religious movement.