On 23 September 1845 Ruskin wrote to John James Ruskin:
I have been quite overwhelmed today by a man whom I never dreamed of - Tintoret. I always thought him a good & clever & forcible painter, but I had not the smallest notion of his enormous powers.
On 24 September 1845 he wrote:
I never was so utterly crushed to the earth before any human intellect as I was today before Tintoret. ( Shapiro, Ruskin in Italy: Letters to his parents 1845, pp. 210 -211)
For Vasari, Le Vite, Testo V.468, Tintoretto was a careless painter who, like others of the Venetian painters lacked a clear grasp of the 'disegno' which marked out the work of Michelangelo, the distinction between the Florentine and Venetian schools, and the superiority of the Florentines. Reynolds reflected and helped to establish in England a consensus around such views about Tintoretto. See Vasari on Tintoretto and Reynolds on Tintoretto.
Ruskin challenged this consensus. The references to Tintoretto in Modern Painters II, and particularly perhaps in the chapter on 'imagination penetrative', were important in England in establishing the reputation of Tintoretto. S tones of Venice III (1853), particularly the Venetian Index to that volume, develops and extends his analysis of Tintoretto's work. The 1871 Oxford lecture on 'The relation between Michael Angelo and Tintoret' revisits the controversy between the Venetian painters and the Florentine school which had begun with Vasari, and had been continued by Reynolds. It concludes with an analysis of the large Paradise in the Ducal Palace as the 'thoughtfullest as well as the mightiest picture in the world' ( Works, 22.105).
See Ruskin and the Italian School.