Complex sentence: His first major work was 1885's "The Potato Eaters", from a time when his palette mainly consisted of sombre earth tones and showed no sign of the vivid colouration that distinguished his later paintings.
Split into simpler sentences: His first major work was 1885's "The Potato Eaters". His palette at the time consisted mainly of sombre earth tones and showed no sign of the vivid colouration that distinguished his later paintings.