The article aims to reconstruct the salient moments in the building and decoration of the chapel of Saint Nicholas situated on the first floor of the old bishops' palace in Pistoia, starting from the time of its foundation in around 1170-1180 up to the time of the early 14th-century renovation. Interpreting the history of the oratory in parallel with the development of relations between the Pistoian episcopacy and the municipal government, the study focuses on the one hand on pinpointing a precise moment in which to date the building of the chapel and on the other identifying the specific context which constituted the precondition for the new pictorial cycle of the 14th century, and thus provided the basis for its iconographic theme. As regards
the former question, it would appear necessary to interpret the construction of the oratory – built above the 'old' sacristy of the chapel of Saint James in Pistoia cathedral – in the light of the conflicts between Comune and bishopric at the end of the 12th century; a dialectic which, as already suggested by historical studies, had also found expression in the control over the prestigious cult of Saint James. In this context, building the episcopal chapel over the sacristy, where the apostle's precious relics were kept, would reflect not only the intention to draw on distinguished 'double' sacella models, formed of two superimposed rooms, but also the will, on the part of the bishop, to reaffirm the special tutelage he exercised over the Saint's treasure, in opposition to the Comune's attempts to assume control over the management of the worship of Saint James and the institution in charge of it, the Opera di San Jacopo. As for the critical interpretation of the 14th-century painting cycle, it is important to draw attention to the partially modified use of the chapel of Saint Nicholas from the 13th century on, and, at the same time, to the simultaneous radical change in the bishopric's relations with the municipal government.
While the oratory, being incorporated into the structure of the bishop's palatium, finally lost its integration in the complex revolving around the sanctuary of James – that is, its relationship with the sacristy, with the consequent accentuation of its 'private' function and as the seat of the cult of Saint Nicholas – the Comune, having removed every residual trace of temporal power from the bishop, started to interfere in an increasingly blatant way in spheres of episcopal jurisdiction, going so far as to occupy itself, by the end of the century, with matters traditionally lying within the domain of the pastoral government. It is precisely in connection with this particular context that we would wish to interpret the new mural decoration of the Saint Nicholas oratory, which aims to reaffirm the validity of diocesan power through images exalting the illustrious roots of the authority and role of the bishops, with a self-promotional and legitimizing function. It is possible, most notably, to link the iconographical programme with the ecclesiastical commitment of Ermanno Anastasi (1307-1321) – a bishop originally from Foligno, who was moved to the see of Pistoia by Pope Clement V – who sought to again strengthen the old prerogatives and privileges of the episcopate through the convocation of an important diocesan synod that met several times between 1308 and 1313.
Lastly, the paper illustrates the similarities linking the frescoes of the episcopal oratory with the pictorial production of Pisa at the beginning of the century (notably, with the author of the dossal of the Museo Diocesano of Oristano, with the first part of the activity of the 'Maestro di San Torpè' and, in particular, with the miniaturist who illuminated the Psalter-Hymnal no. 528 of the University Library in Pisa). Comparison with the salient episodes of the proto-14th century situation in Pisa, moreover, is the occasion for a brief revision of the city's scene before Traini, still deserving of specific research and investigation.