"Kloestevl und Jagdschloss in Hinterviss, Tyrol," 1874. Pen and Ink on paper by Robert Koehler.

"Self Portrait," 1881. Pen and ink on paper by Robert Koehler.

"Woman in a Rocking Chair," c.1885. Watercolor on paper by Robert Koehler.

"Old Woman looking down," c.1885. Etching by Robert Koehler.

"The Strike," 1885. Print by Robert Koehler.

Robert Koehler, c.1907.

The studio of artist Robert Koehler in Minneapolis, c.1900.

"Self Portrait Behind an Easel," 1881. Charcoal on paper by Robert Koehler.

"Rainy Evening on Hennepin Avenue," c.1902, Oil on canvas painting by Robert Koehler.

"The Socialist," 1885. Etching on paper by Robert Koehler.