He was his own chief teacher.

Outside his studio he wrote upon a sign to inform or attract pupils--'The design of Michelangelo and the colouring of Titian.' Profound study of the works of these two masters is manifest in his own.

Like Michelangelo he worked passionately rather than with the sober competence of Titian.

His thronging visions, his multitudinous and often vast canvases are a surpassing record.

Prolonged study of the human form had given to him, as to Michelangelo, a wonderful power of drawing groups of figures.
His mere output was marvellous, and much of it on a grandiose scale.
He covered hundreds of square feet of ceilings and walls in Venice with paintings of subjects that had been painted hundreds of times before; but each as he treated it was a new thing.