Complex sentence: He apprenticed with the Detroit Calvert Lithograph Company for seven years but in 1890 he traveled to Europe where he trained with Professors Johann Herterich, Ludwig Schmid, and Adolph Menzel.
Split into simpler sentences: He apprenticed with the Detroit Calvert Lithograph Company for seven years. In 1890 he traveled to Europe where he trained with Professors Johann Herterich, Ludwig Schmid, and Adolph Menzel.