Lewis toured Europe in 1827, the year he began to paint in watercolour, then travelled in Spain and Morocco between 1832 and 1834. The drawings he made were turned into lithographs by him and other artists, and published as "Sketches and Drawings of the Alhambra, made during a Residence in Granada in the Years 1833–4" (1835) and "Lewis's Sketches of Spain and Spanish Character" (1836). For a while he became known as "Spanish Lewis", to distinguish him from "Indian Lewis", his brother Frederick Christian, who went to India in 1834 before dying young.