Lewis is considered one of the most important Victorian artists to visit the Middle East. The son of Frederick Christian Lewis, a successful engraver, he gained early success as a painter of animals and sporting subjects. In 1840-1 Lewis travelled, via Italy, Greece and Turkey, to Cairo, where he remained for the next ten years. Lewis made nearly six hundred watercolours and drawings throughout the decade. These works, together with the Oriental costumes and artefacts he collected, became the foundation of his paintings of desert encampments, harem interiors and mosques that he made and exhibited after his return to London in 1851. Lewis worked in watercolour from the 1830s, but from the late 1850s returned to working in oils in the hope of making more money and on the advice of John Ruskin. His paintings, however, retained their minuteness of detail.