While Ruskin was elaborating and completing his _Modern Painters_, he was likewise engaged upon works bearing on the kindred art of architecture. His chief writings upon it are _The Seven Lamps of Architecture_ (1849) and _The Stones of Venice_ (1851-1853). His appointment in 1869 as Slade Professor of Fine Art at Oxford greatly stimulated his activity. His reputation had then reached nearly its highest point. He interpreted his duties seriously, and threw himself with ardour into the work. Quite a number of his smaller publications--among them _Aratra Pentelici_, _The Eagle's Nest_, _Ariadne Florentina_ and _Love's Meinie_--are the outcome of his tenure of the professorship. His second tenure of office, beginning in 1883, produced _The Art of England_ and _The Pleasures of England_. He moreover made himself an art-guide to travellers in Italy; and hence his _Mornings in Florence_ and _St. Mark's Rest_. This great body of art-criticism is all bound together by a few fundamental principles; and it is perhaps his fidelity to principle, hardly less than the magnificence of his style, that has won for Ruskin a popularity denied to other critics of art. It will be useful to regard his critical work from two points of view: its rise in negation and opposition, and its issue in positive doctrine. Ruskin, like every man who has had much to teach, begins by being a protestant. He finds that all is _not_ for the best in the best of all possible worlds, and his effort is first to uproot what is bad, and secondly to encourage and foster what is good. The objects of his dislike have been so often denounced by him that all know what they are. Materialism, utilitarianism, a sordid industry merely concerned with the accumulation of wealth, and caring little either for its use or for the quality of the thing produced--these have been the objects of Ruskin's life-long hatred. The merits of his method of dealing with them must be touched on later; here it is enough to notice that the motive for his work on art is the pressing need to find some foundation, other than these, for the beautiful and good. Though Ruskin was not of the Oxford movement, he was stimulated by much the same sympathies and dislikes that produced it; and it is interesting to note how Pre-Raphaelitism in art, Ruskin's art-criticism, and the poetic and religious movements of the middle of the century, all show various forms of the same revolt against the deification of matter.