The buildings belonging to the UNESCO site also represent an important innovation with regard to the decorations with which they were adorned, especially internally. The techniques employed, stucco and fresco, had existed from antiquity, but variation in the way they were combined – with the prevalence of one or the other – conferred on Longobard monumental building complexes an original and opulent appearance, which differs from one to another.
Most of the paintings known derive from the widespread and refined Roman-Byzantine school. The use of the cultivated models of this tradition was facilitated by the presence of craftsmen who had fled to Italy from the East as a result of Iconoclastic persecution. To these workers in particular must be attributed the extraordinary series of paintings in Santa Maria foris portas, Castelseprio, which portrays the story of Christ with reference to the Infancy Gospels, in accordance with the repertoire elaborated by the Byzantine school from the late 7th century onwards.
Notwithstanding its fragmentary condition, the decoration of San Salvatore in Brescia is without doubt one of the most lavish that survive from the Early Medieval period, as too is that of the Cividale Longobard “Temple”, which is similar with respect to historical circumstances and style (in both cases a note of colour is added to the stucco by the addition of small green and blue glass bulbs at the centre of the flowers).
The Brescian monument exhibits a particularly original fusion of stucco and painting, and a precocious revival of the coffered ceiling in stucco. Eclecticism in the combination of Ravenna-based and Roman models and in the use of stuccos on the architectural parts (arch undersides and faces) – as well as in motifs both traditional (the naturalistic treatment of figures and attention to architectural and landscape backgrounds, of Greco-Roman tradition) and Britannic – make this a unique synthesis.
In Langobardia Minor, the painting in Santa Sofia is unparalleled for the vivacity of its scenes, naturalistic style and degree of expressiveness. The frescoes preserved in the presbytery of the Clitunno “Temple”, on the other hand, belong to the main current of post-Classical Roman tradition.
However, the greatest originality is to be seen in stucco decoration, above all in the Cividale “Temple”, which is unmatched in Italy. The renewed interest in the Longobard period in architectural decoration in stucco is probably related to the existence of a strong and similar tradition since Roman times in Merovingian territory; plaster was widely available in the vicinity of Paris. But it is likely that the great growth in gypsum-plaster ornamentation in the 8th and 9th centuries, and the presence of highly specialized craftsmen, derives from oriental tradition and the Umayyad conquest of Spain in 756.
All Longobard artistic activity was thus inspired by both tradition and innovation; context determined preferences for local or oriental practices, for new modes of expression from “Barbarian” Europe, the Byzantine East, or indeed contemporary Arab culture.
Stucco has been used from ancient times as a covering for any kind of surface, architectural or of statues, as a preparation for the subsequent application of colour. To a paste of slaked lime and pozzolana, powdered marble or gypsum plaster was added; this was applied to fresh wall-plaster and modelled using a spatula or with the fingers. Vitruvius (De Architectura VII, 3,3) and Pliny (Naturalis Historia, XXXVI, 176) indicate how a good mixture may be prepared.
The Romans used this type of decoration more for external than internal surfaces. Artistically notable examples are to be seen at Pompeii in the public baths and elsewhere (Stabian Baths, Forum Baths, Temple of Isis etc.) and in Rome (Domus Aurea, Hadrian’s Villa, Ostia Antica); one of the most important examples is the late 1st century BC complex beneath the Villa Farnesina.