Describing the status of Lorenzo Ghiberti and Filippo Brunelleschi relative to their many colleagues at work on the cathedral of Santa Maria del Fiore in Florence in the early 1420s, Margaret Haines observes that 'Their position was somewhat superior ... reflecting their artistic and cultural expertise.'1 Expectations of artists, how they were seen and the ways in which they saw themselves and each other in fifteenth-century Florence are often caught up in the idea of 'expertise'. However, quite what constituted 'expertise' is uncertain and hard to define.A text like Ghiberti's Commentarii, from which it is possible to glean some sense of how he perceived his own expertise and that of his peers, is therefore a useful, if not invaluable tool. The second part of Ghiberti's text in particular is illuminating as to how he understood various types of 'expertise', how they might be acquired and to what useful end they had been put. The Commentarii, though, are themselves elusive of definition. Not only is the surviving text corrupt, but locating the metanarrative (assuming there is one) of a group of writings that includes elements of history, biography, autobiography, criticism, scientific treatise and commonplace book is difficult to say the least.The accepted title of Ghiberti's writings comes not from the extant manuscript copy but from a reference to it in a nineteenth-century work, Cicognara's Storia della scultura.2 Lorenzo Bartoli, in his 1998 edition of the texts, comments that 'The Commentarii, in particular in the papers on perspective, have the form of a zibaldone and not of a treatise structured in three parts (or commentarii) as they have been interpreted by Schlosser.'3 Bartoli goes on to point out that it is only in relation to the second part of his writings that Ghiberti himself uses the term commentario, preferring to refer to the first part, straightforwardly enough, as 'questo primo vilume'. The word Schlosser used, Denkwurdigkeiten, is no more helpful than commentarii or indeed zibaldone as a descriptor for all three sections of the writings, at least in the sense of 'memoirs', which was the one that Schlosser intended.4 If, however, the word is seen less as defining the specifically literary category of memoir and more generally as a description of 'things worth remembering', then it perhaps comes closer to embracing the scope of Ghiberti's writing.This scope is wide, but Ghiberti's 'things worth remembering' appear to be directed towards a particular end: the provision of some sort of literary resource that will serve to enable painters and sculptors to avoid the twin pitfalls of being either unlettered or over-reliant on theory.5 In the first section, 'Arte Antica', the material from Pliny and Vitruvius of which the book is largely comprised is parenthesized by statements that seem to underline this. Near the beginning, Ghiberti lists (in a quotation from Vitruvius) the liberal arts in which the sculptor or painter should be instructed and proficient.6 Then, in the penultimate paragraph, he relates how 'In this first volume, I have explained the things which the sculptor, or rather the statue-maker, and the painter need to know in order to gain mastery.'7 Ghiberti's object in writing and in his selection of material appears, therefore, to be explicitly didactic. Yet it also appears that he has not, in fact, done what he claims in that penultimate paragraph; for he certainly has not gone far in instructing his readers in 'all these liberal arts: grammar, geometry, philosophy, medicine, astrology, perspective, history, anatomy, theory of design and arithmetic'.8This apparent failure is not what it seems. Ghiberti himself is manifestly comfortable with the extant classical literature of art, insofar as it existed in vernacular translation, and he displays here a commensurate confidence in the abilities of his readers, assuming that his iteration of the liberal arts as the basis of the artist's intellectual life will be understood. …