Luca della Robbia (1400-1482), Florentine sculptor, worked on the cycle of reliefs begun by Giotto on the Campanile of Florence cathedral, and made the first of the two singing galleries, and the bronze doors of the Cathedral sacristy. Vasari stresses particularly his invention of the technique of glazing terracotta to protect it from 'the injury of time'. According to Vasari his first works using this technique were simply white, but then to everyone's 'wonder and admiration' he introduced colour to them ( Vasari, Le Vite, Testo III.53). Among his first patrons was for these coloured reliefs was Piero di Cosimo de' Medici, and a major trade in his work developed throughout Europe. Examples of white and coloured glazed medallions were made for Orsanmichele in Florence.
At Works, 4.301, Ruskin cites Luca della Robbia as providing a painful example of the effects of colour on solid forms. In a letter to John James Ruskin from Florence on 29 May 1845, he writes of Luca della Robbia's coloured porcelain reliefs on the Ospedale del Ceppo in Pistoia that they have the most 'vulgar effect conceivable, looking like the commonest signpost barbarisms. And yet if you struggle with yourself, and look into them, forgetting the colour, you find them magnificent works of the very highest merit, full of the purest sculptural... feeling, and abundant in expression, grace of conception and anatomical knowledge. (See also Shapiro, Ruskin in Italy: Letters to his parents 1845, p. 87, and quoted in a footnote at Works, 4.300)
Ruskin kept a white Nativity by Luca della Robbia in his study at Brantwood. In Works, 33.313 Ruskin describes Luca della Robbia as having a pivotal role between the Gothic and the Classical, describes his work as 'delightful to truest lovers of art in all nations, and of all ranks', and reports an occasion when a three year old girl kissed the child on his Nativity when it was on the floor at Brantwood.