John Ruskin (1819-1900) was the most influential art critic of the nineteenth century. A watercolorist, a botanist, a moralist, a sensualist, a socialist, an economist, a Romantic, a prophet, a priest, and a poet, his writings integrate the aesthetic with moral purpose and ecology. He established his reputation with The Stones of Venice and his masterwork, Modern Painters, then held the Slade Professorship of Art at Oxford University from 1870 to 1878.