This cast of an acanthus boss is one of ten examples of sculpture from St Mark's that Ruskin described as 'pure thirteenth-century of rarest chiselling' (Works, 24, pp. 286-291). Ruskin thought the acanthus bosses 'the most instructive pieces of sculpture' in the Museum.

It is interesting to compare the detail preserved in Ruskin's cast with the damaged surface of the same boss as seen today on the outer archivolt of the central door of St Mark's.

Ruskin on Bosses

Enlarging on the significance of ornamented bosses in Lectures on Architecture and Painting (1853), Ruskin asks his reader to 'Imagine the effect on the minds of your children [...if] every boss on your buildings were, according to the workman's best ability, a faithful rendering of the form of some existing animal, so that all their walls were so many pages of natural history' (Works, 12, p. 66).

Ruskin extends this principle of education to comment on the conditions of labour: 'And finally, consider the difference, with respect to the mind of the workman himself, between being kept all his life carving [...] repetitions of one false and futile model, -- and being sent, for every piece of work he had to execute, to make a stern and faithful study from some living creature of God'.

Ruskin even entertains the idea that such a boss might inspire the work of nature. In 'Wise Art and Wise Science', he recalls visiting John Gould, an ornithologist who showed him 'the nest of a common English bird'. The bullfinch had dexterously assembled a structure, whose 'twigs it had interwoven lightly, leaving branched ends all at the outside, producing an intricate Gothic boss of extreme grace and quaintness, apparently arranged both with triumphant pleasure in the art of basket-making, and with definite purpose of obtaining ornamental form.' (Works, 22, p. 157).